Contact Your Banking Institution
Contact your banking institution. Most states consider checks that are in excess of 6 months old, "stale dated." This means they can be cashed, but the bank can choose to refuse the check. By calling your bank, you become more of a informed consumer. The bank can give you ideas of how to successfully cash the check, as well.
Take a Chance and Cash the Check
Many checks don't have an expiration date on them. Also, bank tellers may or may not check for an expiration date. However, the employer may have put a "stop payment" on your long overdue check. Deposit the check into your bank account. Wait until the check clears before spending the money.
Call Employer Who Issued the Check
Contact the employer that issued the check, and have him re-issue another one for you. This ensures no stop payments or bounced checks.
You Issued a Personal Check but It Hasn't been Cashed
Put a stop order on it, if it is more than 6 months old. If you want to make sure it doesn't get cashed, make sure to renew the stop order on it every six months.