If a thing is lent for use for a specified time or purpose, it must be returned to the lender without demand, as soon as the time has expired, or the purpose has been accomplished. In other cases it need not be returned until demanded.
Cal. Civ. Code § 1895
Loan for Use
Enacted 1872.
Official source: California Legislative Information. Reproduced from public-domain California statutes; confirm against the official source for the current text. Not legal advice.