I use pill comfortably for about a year after their expiration date.
But since medicines lose potency over time, I can't use them reliably if they're too old. ie. If I still have pain after taking the usual amount, do I have something serious wrong, or did I just take too small a dose of active ingredient?
Cream I almost never check for an expiration date. It's rarely dangerous to put on more than recommended.
[Different topic: Never overdose on tylenol/ acetaminophen (it's dangerous to the liver). for example, if you take a cold medication with tylenol, don't take more tylenol ]