Legal Question in Civil Litigation in California

If you want to sue for the full amount, you must sue before the SOL runs on the first payment. If you miss that deadline you can still sue for the second payment until 4 years after it was due.

If full payment was due by a certain date with a written contract, then you have only four years from that date to file sue for breach. If you are timely, and if serious about getting counsel to help you, feel free to contact me.

If you have passed the SOL date, you can still try to collect, urging 'moral' obligation to repay. It's worth a try.

I agree with Mr. McCormick's overall advice, but not his legal reasoning. Where a contract contains multiple performances, a failure of a party to perform one part of the performance allows the aggrieved party to either treat it as a breach of the entire agreement, or to sue later when all of the terms are breached.

But don't risk your entire case on an assumption that the judge is going to recognize such a obscure caveat of law. It is better for you to not take the risk at all and file the lawsuit within 4 years of the first breach.