On average, a cashier's check is good for 3 years. Here's why....
Here's a dirty little secret about cashier's checks: Even though most of them have an expiration date, typically 60 or 90 days after the date of issue, they don't truly expire at that point in time. The "best before" date is put on there as a method of speeding the use of the check as a cash equivalent.
On the other hand, those who try to push the term limit of a cashier's check may run into trouble with state abandonment laws. For example, one individual trying to collect on a cashier's check some thirty years after it was issued was told that the issuing bank would no longer honor it.
In the Golden State, as an example, a cashier's check with an expiration date of 60 or 90 days is still good for up to three years from the date it was issued. However, once the item crosses that 36-month threshold, it becomes subject to California's abandoned property laws.
At that point, a bank in the state can legally stand its ground and refuse to honor the financial obligation of the next best thing to cash. It's rare, beyond instances where a cashier's check is lost or misplaced, for such a document to be hoarded for a period of years. It is typically an instrument of immediate business, renter, purchaser, and other time-sensitive transactions.
In recent years, cashier's checks have been targeted by foreign criminals for scams promising false lottery winnings, and by some very bold domestic scam artists. One for example actually tried to use a fake cashier's check to purchase a home. It was actually a real cashier's check, but they then altered the amount, by a cool, extra $100,000.
Counterfeit cash remains rarer than counterfeit checks, so where possible, state Attorney General offices recommend getting the payment in cash rather than by cashier's check. But if the payee, or the person making the payment, prefers not to handle large amounts of bills, then a cashier's check is always a better option than a money order.