Software Engineering is an interesting mix of practice and theory. On the theory side, you should make a habit of browsing / googling for things that are a good intersection of interesting to you and novel. Be forewarned, some of the common places to get information (like stackOverflow) can be very intimidating.
The standard expiration date for most checks is 180 days (six months) and personal checks are included in this policy. In the United States, banks are privately owned and not government operated so banks do have the right to refuse your deposit if there happens to be any suspicion of the item's negotiability.
If the check has a printed expiration date it is often located near the issue date or the signature line. Banks can allow acceptance of a check older than 180 days, as long as they accept it in good faith that it is still valid. However, if the check is no longer a valid payment, the bank has the legal right to withdraw funds from the receiverâs in-house account to cover the loss.