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.
For example most checks are good for 90 or 120 days. If I have a cashier's check and don't see an expiration date on it, does it mean I can cash it even 5 years in the future?est Answer: Technically NO checks expire unless they state ON THE FACE of the check that they expire on X date, or Y days after issued. However, banks are NOT required to honor 'stale' checks, and US banks almost universally consider checks stale after 6 months.