How long do I have to sue over debt collection on an account in California?
Answered for: California
(b) An action to recover (1) upon a book account whether consisting of one or more entries; (2) upon an account stated based upon an account in writing, but the acknowledgment of the account stated need not be in writing; (3) a balance due upon a mutual, open and current account
The statute states 4 years for debt collection on an account. When that clock starts, and whether it can be paused, are separate questions this entry does not answer.
This answer is true in California and nowhere else on this site. Another jurisdiction is another answer, or an honest gap: see what has been read for California.