I've also never replaced a helmet due to age. Mine is probably 6, or going on 6, years old. It's one of those $500 GPA's so I'm not exactly rushing out to go replace it (I do have my eye on a fancy new one though..but I need to come up with $450 for it

). I don't
think I've taken a fall in my GPA as I haven't fallen in years but with 5x a week regular use it's getting a little icky and worn so I want to get it replaced!
If there is even a remote chance that you hit your head, go get your helmet replaced. As previously mentioned, a working brain is worth every penny of that $40 :)