I cleaned, relubed, and installed 4 new CV boots on the axles currently on my Audi. Did so, for the Auto-2-manual swap. ;o)

Both outer CV boots opened within a few hundred miles of each other around ... jeez, maybe 130k miles. A while ago. Unfortunately some crap (gravel?) got in one of them and destroyed it. A new CV joint from a local parts place was going to cost in the neighborhood of $300, but a rebuilt axle from a different local place was less than $100 so I went that route. (There's a longer story associated with finding the rebuilt axles which involves an embarrassing goof which I won't get in to here)

Two nice things (well three, if you include cost) I found about the rebuilt axles: much quicker to install, and you don't have to deal with that horrible, horrible grease.

i have 135k on the car and have replaced 4 of them.