There is no set or hard-and-fast timeline: the insurer can take essentially as much time as it likes, subject only to at some point, if the insurer does not act within a "reasonable" time frame, there may be a lawsuit--by the insured, if his own insurer is not paying him, for breach of contract (for violating the contractual--since an insurance policy is a contract--obligation to pay for a claim); or by the other driver, against the at-fault driver, if the at-fault driver's insurance doesn't offer to settle. Only a lawsuit--or at least the threat of one--can move things along is the insurer is determined to not make a decision or offer anything.