Hey, so I am tempted to pick up a Trek Circuit helmet from someone who has only used it a few times for only $40.

I already have a helmet though, and I was wondering---if I stored my current helmet (Giro Indicator), which has probably only around 30 hours of use, in the closet, would it still be safe to use if I came back to it years later? For example, if I stored it now, could I reuse it again say...from 2015-2018 (assuming it doesn't crash)?

PS-offtopic: I won a 2012 Bell Sweep for $73 shipped off ebay, good deal or no?