While the actual isobutane/propane fuel mix does not expire, you should always carefully inspect the canister before hooking it up to your stove. Always inspect it carefully for rust, punctures, or a deprecated valve seal.
Here’s a tip to help you keep track of your canister’s lifetime:
After a trip, weigh your canister and use a sharpie to record its weight on the underside. Before heading out on your next adventure, weigh the can again to make sure the weight hasn’t decreased. If it has, you know your canister is suffering from either a puncture or leaky valve seal.