Legal Question in Construction Law in California

There is no bright line time limit, but rather an issue of whether it has been so long as to lead a reasonable prime contractor to believe the subcontract has been abandoned. In addition, if the contractor wants to be sure to be protected against a wrongful termination of contract claim, they should send notice of belief of abandonment and demand for performance, in writing, with proof of delivery. If the subcontractor ignores that, it's a pretty good case to terminate the contract for abandonment. If it gets to that, the contractor should also send a formal termination for abandonment notice before hiring another sub to finish the work.