Spar life.
It may interest Piper owner's to know the Spar Life AD has had a revision, which states the components (wing spar) must be retired OR inspected IAW an approved inspection regime at 11000 hours TIS. (PA 32 etc)
Initially there was no such approved inspection however there is now..( Actually for a few years now). My PA32-300 had one at 1099.6 hours and is in the process of having another one.
The inspection regime was created by Michael Punshon, an engineer in Townsville and is CASA approved and gives a further 3000 hours time in service before another is due. If the spar and carry through keep on passing, then effectively there is no throw away life limit.
It's not cheap but you don't have to sell your first born to pay for it either.