I agree with FH, if stored smartly they will last a very long time. I have used 1% cortizone creme over 5 years old, and it worked perfectly. Also used some wart remover over 10 years old and it worked fine. Most of my analgesics are over the expiration date, and they work just fine also. Of topic, but just a quick note about bleach expiration. I have been experimenting with very old bleach that I have. It may not be full power and you can smell that it is not, so I just add a tad bit more to what ever I am doing and it also works just fine. Very little ever gets tossed at my house. Rotation is key, which explains why I have so much old stuff.
"Study men...A gun's only a tool. You can master a gun if you got the knack. Harder to learn men."
-Morg Hickman (Henry Fonda) "The Tin Star" 1957, a very good movie.