Posted in Contract, Corporate Law
By Tony Liu, Founder and Principal Business Trial Attorney
In Summary
When a written contract no longer reflects how the parties actually do business, the difference can matter if a disagreement develops. Years of accepting different payment terms, delivery schedules, responsibilities, discounts, or approval procedures may become relevant to how the relationship is evaluated. Before trying to “fix” an outdated agreement, identify where the contract and actual practice diverge and which differences create meaningful risk.
The Contract in Your Files May Describe a Relationship That No Longer Exists
Your agreement says invoices are due in 30 days. For the past four years, everyone has operated on 60.
The contract requires written approval before certain work begins, but approval has routinely happened through email or a phone call. Responsibilities have shifted. Discounts became standard. Delivery dates changed. Nobody formally amended the agreement because the relationship worked.
Then something goes wrong, and someone pulls out the original contract.
If your contract does not match business practices, the written document still matters—but it may not be the only thing that matters. Under California law, later agreements and, in some circumstances, the parties’ conduct can become relevant when determining whether contractual obligations were modified or waived. California’s current civil jury instructions specifically tell jurors considering modification to look at the parties’ words and conduct.
That makes the gap between the document and the real-world relationship worth understanding before there is a dispute.
For companies already concerned about conflicting interpretations of an agreement, an Irvine corporate disputes lawyer can help evaluate both the written terms and what happened afterward.
Why Does It Matter If Your Contract and Business Practices Are Different?
The problem often stays hidden while everyone is getting along.
Both companies know invoices are routinely paid later than the contract requires. Everyone understands which approvals are actually necessary. Nobody objects when deliveries arrive according to the schedule the parties have followed for years.
A dispute changes the incentives.
Suddenly, one side may say, “The contract requires this.” The other responds, “That is not how we have operated for years.”
Neither position should automatically be assumed correct.
California recognizes that written contracts can be modified in certain circumstances. The state’s official civil jury instruction on contract modification also recognizes that whether the parties agreed to a change may turn on what a reasonable person would conclude from their words and conduct.
That distinction can become important when the disagreement involves money, deadlines, scope of work, approval authority, termination, or another material obligation.
What Does “Course of Performance” Mean?
Course of performance generally describes how parties repeatedly behave while carrying out a particular agreement. In transactions where the concept applies, repeated performance that the other party knows about and accepts without objection can become relevant to understanding the parties’ agreement.
It does not mean every departure from a contract rewrites it.
Can the Way You Actually Do Business Change a Written Contract?
Sometimes conduct matters significantly. But “we have always done it this way” is not, by itself, a complete legal analysis.
California Civil Code § 1698 recognizes several ways a written contract may be modified, including by another writing and, under specified circumstances, through an oral agreement. The statute also preserves the possible application of principles such as waiver and estoppel in appropriate cases.
The important question is therefore not simply whether actual practice differs from the document. You need to understand why it differs, how consistently it differs, what both sides knew, and what the agreement itself says about changes.
What Is the Difference Between Modification, Waiver, and Interpretation?
These ideas are easy to lump together, but they ask different questions.
Modification asks whether the parties actually agreed to change an obligation. California’s current jury instructions recognize that an agreement to modify may sometimes be inferred when the parties’ conduct is inconsistent with the written contract in a way that supports the conclusion that they intended a change.
Waiver concerns whether a party gave up the ability to insist on a particular right or requirement in the circumstances at issue.
Interpretation is different again. Conduct may sometimes help explain what the parties understood contractual language to mean.
Knowing which issue you actually have can substantially change the analysis.
What If the Contract Says All Changes Must Be in Writing?
Do not assume that sentence ends the inquiry.
A written-modification clause is important and should be reviewed carefully. Yet California law recognizes circumstances in which an executed oral modification may matter even when an agreement contains a writing requirement.
Rules can also differ depending on the type of contract. For transactions involving the sale of goods, for example, California’s Commercial Code contains specific provisions governing modification and waiver. An attempted modification that fails certain formal requirements may still operate as a waiver in some circumstances.
That is one reason the entire agreement and the nature of the transaction need to be considered before anyone concludes that an informal change either definitely counts or definitely does not.
What Contract-Practice Gaps Should You Look For?
An outdated business agreement does not necessarily need to reproduce every operational detail. Focus first on differences that could affect money, control, performance, or the ability to exit the relationship.
Look closely at these eight areas:
- Payment timing. The contract requires payment within 30 days, but 60-day payment has become routine.
- Pricing and discounts. Recurring discounts, credits, or pricing formulas were never added to the agreement.
- Delivery schedules. Both sides routinely work with deadlines different from those originally negotiated.
- Scope of services. One party now provides work the original agreement barely addresses—or does not mention.
- Division of responsibilities. Tasks have gradually moved between the parties.
- Approval procedures. Formal approvals have been replaced with emails, calls, or routine autonomy.
- Performance requirements. Both sides consistently accept performance different from the technical contract standard.
- Renewal or termination procedures. The working relationship has developed practices that differ from the written notice or renewal process.
Not every mismatch deserves the same attention.
A minor invoicing procedure may carry much less risk than an informal change involving pricing, exclusivity, ownership, termination rights, or authority to approve significant expenses.
Can the Other Party Suddenly Enforce the Original Contract?
This is often the question management actually wants answered.
If the parties are not following the written contract, can one side suddenly decide that the original terms control again?
The answer depends on the agreement and the history.
In the sale-of-goods context, California law expressly addresses course of performance and permits contract terms to be explained or supplemented in certain circumstances by course of dealing, course of performance, or usage of trade. The Uniform Commercial Code similarly recognizes that repeated accepted performance can be relevant to meaning, waiver, or modification.
That does not create a universal rule that years of flexibility permanently erase the written provision.
Does Accepting Something for Years Mean the Original Term Is Gone?
Not necessarily.
There is an important difference between tolerating an exception and agreeing to a new rule. Likewise, consistently accepting the same different performance for years can present a different factual picture than overlooking something twice.
Ask:
- How long has the different practice continued?
- Has it been followed consistently, or only occasionally?
- Did both sides know the practice differed from the written agreement?
- Were any objections raised along the way?
- Was the different treatment ever described as temporary or an exception?
- Do emails or other communications acknowledge the change?
- Has either party relied on the established practice when making business decisions?
- What does the agreement say about modification or waiver?
The answers help establish whether the operational history is background noise or something that may materially affect the parties’ positions.
What Evidence Shows How the Relationship Actually Operated?
Do not wait until the relationship deteriorates to reconstruct five years of business history.
When Focus Law evaluates contractual disputes, an important part of understanding the problem is comparing what the agreement requires against what actually occurred. That can reveal whether the dispute is really about one alleged breach or a larger disagreement over the rules the parties have been following.
Start with:
- The original contract and all amendments
- Renewal documents
- Invoices and payment records
- Purchase orders
- Email approvals
- Pricing and discount records
- Delivery histories
- Internal procedures
- Meeting notes
- Communications discussing exceptions or changed responsibilities
Look for patterns rather than isolated departures.
One invoice paid 30 days late may show very little. Dozens of invoices issued, paid, and accepted on the same different schedule over several years tell a more developed factual story.
If those patterns are already becoming a source of disagreement, understanding them early can help define the real issues in an Irvine corporate dispute.
When Should You Update an Outdated Business Agreement?
“Update your contracts regularly” sounds sensible but does not tell a business owner much.
A better approach is to watch for material drift.
Consider reviewing the agreement when actual practice has changed how the parties handle:
- Pricing or payment
- Scope of work
- Decision-making authority
- Performance deadlines
- Exclusivity
- Intellectual property
- Liability allocation
- Termination
- Renewal
- Ownership or control
- Significant approval rights
The objective is not to memorialize every convenience that develops during a long relationship.
Instead, ask whether someone new could read the contract today and understand the important economic and operational rules of the relationship. If the answer is no, management should at least understand what created the gap.
Should You Just Amend the Contract to Match Current Practice?
Not before understanding what you already have.
This is one of the most overlooked risks with informal contract changes. Management discovers that the agreement is outdated and immediately sends the other side a proposed amendment designed to “clean things up.”
That may expose disagreements nobody realized existed.
Perhaps your company believes a discount became permanent while the other side views it as temporary. Maybe one party considers an approval procedure abandoned while the other thinks it merely chose not to enforce the requirement in certain situations.
Before proposing changes, ask:
- What does the existing agreement require?
- Where did actual performance depart from it?
- Which departures were knowingly accepted by both sides?
- Which changes benefited your company?
- Which original protections do you still want?
- Are past obligations unresolved?
- What rules should apply going forward?
A new amendment should solve uncertainty, not accidentally create evidence of a disagreement that was never properly evaluated.
What Should You Do Before a Disagreement Develops?
A contract-to-practice audit can be surprisingly revealing.
- Read the agreement literally. Ignore what everyone “knows” for the moment.
- Mark every provision the parties no longer follow.
- Write down what happens in practice instead.
- Identify when each practice changed and who knew about it.
- Gather records showing whether the practice was consistent.
- Separate occasional accommodations from long-running patterns.
- Prioritize differences involving money, control, performance, and exit rights.
- Review the legal effect before demanding strict compliance or proposing an amendment.
That final step matters.
Abruptly announcing, “Starting Monday, we are enforcing the contract exactly as written,” may seem like the safest response. Depending on the agreement, applicable law, prior conduct, notice, reliance, and other facts, the situation may be more complicated.
For certain sales contracts, for example, California law specifically addresses when a waiver affecting future performance may be retracted and when reliance may affect that ability.
Why Review the Contract While the Relationship Is Still Working?
Because once a dispute starts, the same history may suddenly acquire two meanings.
One side calls years of different conduct a modification. The other calls it courtesy.
One says a requirement was waived. The other says enforcement was merely postponed.
The documents have not changed. The incentives have.
California’s Judicial Council publishes civil jury instructions designed to state California law in language understandable to ordinary jurors, including instructions covering contracts and modification. If a California contract dispute eventually reaches litigation, those underlying questions can become much more consequential than they seemed while the relationship was healthy.
Reviewing the mismatch earlier gives management a chance to understand the problem without automatically turning it into a confrontation.
Frequently Asked Questions
Can a contract change if the parties never signed an amendment?
Potentially. California law recognizes circumstances in which written contracts can be modified through later agreements, including certain oral agreements that have been carried out. Conduct can also become relevant to other issues such as waiver. Whether a particular practice changed the parties’ obligations depends on the contract, facts, and applicable law.
What happens if both parties have ignored part of a contract for years?
The history may become relevant, but ignoring a provision does not automatically erase it. Questions may arise about modification, waiver, interpretation, or the parties’ course of performance. The frequency of the conduct, knowledge of both sides, objections, communications, reliance, and contractual language can all matter.
Can a company enforce a contract term it previously did not enforce?
Possibly, but past conduct should be evaluated first. Whether strict enforcement can resume may depend on the agreement, the type of contract, prior waiver, notice, reliance, and other circumstances. California’s Commercial Code contains specific rules concerning waiver and future performance for contracts involving sales of goods.
Does an email count as a contract modification?
An email can be important evidence, but calling something an “email modification” does not determine whether it legally changed the contract. Its effect may depend on what was communicated, who had authority, whether the parties agreed, the existing contract’s requirements, applicable writing requirements, and what the parties did afterward.
Should we amend an outdated contract before a dispute starts?
It may make sense to formalize material changes, but first determine what the current agreement and historical conduct mean. Understand which practices were mutually accepted, which protections remain important, and whether unresolved past obligations exist. An amendment is more useful when it resolves identified uncertainty rather than simply making the paperwork look current.
Know Which Rules Actually Govern the Relationship
Business relationships evolve. Contracts often do not.
The fact that your business practices are different from the contract does not automatically mean something is wrong. The risk arises when the two sides no longer agree about what those years of different performance meant.
That disagreement may remain invisible until payment, performance, renewal, termination, or another high-stakes decision puts pressure on the relationship.
At that point, “we have always done it this way” and “the contract says otherwise” can become competing versions of the same history.
If your written agreement no longer reflects how the relationship actually operates, Focus Law can help evaluate the contract, the history of performance, and where the differences may create risk. Learn more about our approach to corporate disputes in Irvine or contact us at 714-415-2007.
