i think even if you've had them around for a long time as long as they haven't started to smell funny they're still okay expiration dates are made up to make you buy more friends when your old ones are perfectly fine
My best friend and I have been friends for 20 years, after meeting in kindergarten. My other enduring IRL friendships are about 12 years, all from middle school, and my internet friendships are all 8-4 years old. Plus lots of acquaintances along the way.