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.
Quick Answer. A cashier's check does not have an expiration date and is guaranteed by the issuing bank until the check is paid. The funds of a cashier's check generally must be turned over to the state's unclaimed property custodian after a period of time, according to the state's abandoned property laws. Keep Learning.