Very unlikley in the confines and heat of a cossie engine bay being cooked right next to the turbo, bit different to on a test rig in a nice cool workshop, I test all mine at the place where I repair them also, if I'm feeling lazy I let the lads do it.
As you know the more they output the faster they wear my example was based on a average expected use go drawing even 90 from a 90 alt and it aint going to last long, in use I always say ideally for long life alt needs to be around three times capacity that you regularly draw, not to be on limited time.
tabetha