You may have found an old check and thought this was "found" money, but it could come back to bite you. Cashing that old check might end up costing several times its value in fees. This could happen because banks are not obligated to cash a check older than a few months. However, the date on stale checks is sometimes taken as a guideline, not a hard rule.
It's Up to the Bank
You can deposit a check of any age, but the bank is not required to cash a check older than six months. Thus, it is up to discretion of your bank to cash a stale check. Some banks will accept checks up to 12 months' old as long as you present the check in good faith. This generally means you put the check in a drawer somewhere and forgot about it – there cannot be any suspicion of fraud. Certified checks, which are checks that have been guaranteed by a bank, are different. These checks remain valid more-or-less forever and a bank should always honor it.
Cash Old Checks at Your Peril
Paper check processing is mostly automated these days, so bank officers rarely review the date on a check. In many cases, the check will go through without query. Only a "stop payment" instruction from the payer will alert the bank that the check should not be cashed. There are no guarantees, however. The biggest risk you face when cashing a stale check is that the bank refuses it and charges you a "deposit item returned" fee. Banks usually charge a fee to the payee when they cannot cash a check. The fee varies by bank but will usually set you back between $10 and $30. If you have a check for a small amount, such as a dividend from a stock, you risk the bank hitting you with fees that exceed value of the check.
You Can Still Collect on the Debt
A stale check or one past its expiration date does not mean you cannot collect on the debt. The easiest solution is to contact the payer and ask her to reissue the check or pay you in some other form. It's courtesy to speak to the payer before presenting an old check; otherwise, there's a chance that the payer has forgotten about the check she has written and cashing it may make her go overdrawn.
When to Call it a Day
In practice, banks will cash checks up to a year old. It may take extra time to cash an old check because the bank might need to flag the check and review its legitimacy. Call the issuer of the check to ask if the routing number for his account has changed before cashing it – the check cannot be cashed if it has an outdated routing number. The payer may talk to the bank to cash the old check to avoid the extra costs and time reissuing a check. Beyond a year, question whether it's worth all the hassle to cash the expired check. For checks with a relatively small face value, it may be worth writing off check and chalking the situation down to experience.