Your contract requires payment by the first of each month, but you regularly accept payment on the fifteenth without objection. When the relationship breaks down, can you suddenly treat that same delay as a default? Possibly—but your conduct may complicate enforcement. For California businesses and individuals, understanding contract waiver course of dealing means recognizing when repeated exceptions can weaken contractual rights, what protective clauses can accomplish, and how to restore expectations before a dispute develops.
What is waiver by conduct?
Waiver is the intentional relinquishment of a known right. It can be express, such as a written statement excusing a particular deadline, or implied from conduct inconsistent with an intent to enforce that right. The California Supreme Court explains these principles in Waller v. Truck Ins. Exchange, Inc. (1995) 11 Cal.4th 1, 31 [44 Cal.Rptr.2d 370, 900 P.2d 619].
Failing to enforce a provision once does not automatically erase it. The question is whether the facts show an intent to give up the right. Relevant facts may include what you knew, what you said, how often you accepted departures from the contract, and whether you objected.
For example, accepting one late delivery while expressly reserving your rights differs from accepting late deliveries for months and telling the supplier that the written schedule does not matter. Waiver can concern a specific breach or right without surrendering every protection in the agreement.
Contract waiver course of dealing: why patterns matter
People often use “course of dealing” to describe any pattern between contracting parties. For transactions governed by the California Commercial Code, however, the terminology is more precise. Commercial Code section 1303 distinguishes between:
- Course of performance: Conduct under the current transaction involving repeated occasions for performance, where the other party knows of and accepts the performance without objection.
- Course of dealing: Conduct in previous transactions between the parties that establishes a common basis for understanding their communications and conduct.
- Usage of trade: A practice regularly observed in a trade or industry that may inform expectations.
These concepts can help interpret an agreement. Under section 1303, express terms and any applicable course of performance, course of dealing, and usage of trade must be construed as consistent whenever reasonable. If that construction is unreasonable, express terms prevail over the other evidence, course of performance prevails over course of dealing and usage of trade, and course of dealing prevails over usage of trade. Subject to section 2209, course of performance is also relevant to showing waiver or modification.
That distinction matters: interpreting a term and waiving enforcement of it are different questions. Even a clearly written deadline may generate a waiver dispute if the parties repeatedly disregard it. Outside Commercial Code transactions, communications and patterns of conduct can still provide evidence relevant to waiver.
Common conduct that creates enforcement problems
Waiver disputes often arise from practical accommodations rather than a formal decision to change the contract. Watch for patterns such as:
- Accepting late payments without mentioning the missed deadline or reserving available rights.
- Approving work that does not follow contractual specifications without identifying the departure.
- Allowing services to continue after repeated breaches while communicating that performance is acceptable.
- Telling the other party that a required written approval is unnecessary.
- Repeatedly overlooking notice requirements, then trying to enforce them without warning.
None of these facts automatically establishes waiver. Context matters, including whether the exception was temporary, whether your objection was clear, and whether you knew about the relevant breach.
Estoppel is a related but distinct concern. It generally requires knowledge of the true facts by the party whose conduct is at issue, intent that the conduct be acted upon or conduct giving the other party reason to believe it was so intended, ignorance of the true facts by the other party, and reasonable reliance resulting in injury. If your words or conduct lead another party to believe strict compliance is unnecessary, these elements may support an equitable-estoppel argument. Reliance is not an element of waiver. A business owner should evaluate waiver separately from reliance-based estoppel and, for a sales contract, whether reliance could make retraction of a waiver unjust before abruptly changing an established practice.
What nonwaiver and written-modification clauses can do
A nonwaiver clause may state that accepting late performance or declining to enforce a right does not waive future enforcement. A written-modification clause may require signed approval before contractual terms change. Both can clarify expectations and strengthen your position, but neither should replace consistent conduct.
California Civil Code section 1698 addresses modification of written contracts. Importantly, subdivision (d) preserves rules concerning waiver and estoppel. A clause requiring written modifications therefore does not, by itself, eliminate every argument based on the parties’ conduct.
For sales of goods, California Commercial Code section 2209 distinguishes modification from waiver. Under subdivision (4), an attempted modification or rescission that fails the applicable signed-writing or statute-of-frauds requirements may nevertheless operate as a waiver. Subdivision (5) separately governs retraction of a waiver.
A review of your business contracts should consider both the written protections and how your team actually applies them. Contract language is more useful when invoices, approval emails, and default notices remain consistent with it.
How to restore clear expectations
If you have allowed repeated exceptions, do not assume an immediate demand for strict compliance resolves the issue. Start with a review of the contract and the parties’ communications.
- Identify the departure. Document the requirement, the exceptions, and any objections or assurances.
- Separate past and future performance. A notice about future deadlines does not necessarily revive rights already waived.
- Give clear, timely notice. Explain which requirements you expect the other party to follow going forward and provide an appropriate transition where necessary.
- Assess reliance. Determine whether the other party materially changed position because of your prior conduct.
- Make future exceptions specific. Identify their scope and duration, reserve applicable rights, and follow through consistently.
For sales of goods, Commercial Code section 2209(5) permits retraction of a waiver affecting an executory portion of the contract through reasonable notification, unless retraction would be unjust because of a material change of position in reliance. Other contracts require analysis under the applicable law and facts.
Talk to a California business attorney
If repeated exceptions have made your contract rights uncertain, Itkin Law offers a free consultation to discuss your agreement, communications, and enforcement concerns. Schedule a free consultation or call (424) 603-8888.
This article is attorney advertising and provides general information only. It is not legal advice and does not create an attorney–client relationship. The law changes, and this article reflects the law as of its publication date. Every situation is different — contact us to discuss how the law applies to your exact circumstances. See our full disclaimer.
