I do note that any left over prescription meds I might have on hand have expired and get rid of them appropriately.
I keep Banamine and a small amount of bute on hand for my horse(s) and every spring when the vet is out doing maintenance stuff I replace anything that is outdated. Both meds I am happy to have paid for and not have had a use for before they expire.
Dog and cat stuff, other than buying a full years worth of heartworm/flea stuff at a time, the only prescription meds I have for them are things that are used and replaced as they are used up.
I have no human drugs that I can see replacing once they expire. I can not imagine being able to replace them, even. Will the doctor write a script just so you can have it on hand (not talking epi pens or such here, clearly those are needed to have on hand).