If a Cashier's Check is over 90 days old, you should consider accepting it only as a collection item.
Cashier's Checks (even non-local ones) are Next Day items EXCEPT:
1. If deposited at the ATM
2. If your customer is not one of the named payees on the front
3. If it's a large check, then the amount exceeding $5,000 is not subject to Next Day.
4. If your depositor has been repeatedly overdrawn according to Reg CC definitions.
5. If you have reasonable cause to doubt collectability. NOTE - if this is the case, then you should not accept the Cashier's Check in the first place. If you have already accepted the item for deposit, and later find out it's a counterfeit, then Reg CC no longer applies to the item (since it was never a check in the first place!)
Regulations are a poor substitute for ethics.