do personal checks expire?

[NewtonMP2100]

...check the expiration date....?

[Panopticon]

http://helpwithmybank.gov/faqs/banking.html
Note, the above link {OCC} only regulates national banks. If your bank is 'state chartered', check with the state's banking agency.

[RAMd®d]

And regardless of policies, if a check is inducted via an automated process instead of taking it to a teller, there is a good chance that it will be cashed, as Winston mentioned.