OK, I'll throw a little gas on this fire (pun intended!).

We have to have our fire systems certified/checked/whataver every two years?

If you have an FIA rated cell (as called for in the GCR for most other classes), the FIA certification expires after 5 years and the cell needs to be recertified. None of us do that of course, nor have I ever heard of a tech inspector even asking.

Don't worry about a fire from an old cell, you have a safe fire system!

(And SFI has specs for cages (that we don't use).......but that is another topic.)