That depends on you. Good grease and low impact loads should last.
I have my original driveshafts from the Road Warrior sitting in my storage with 588,238 miles on them.
They are a little sloppy. They have some horrific pits. Maybe a couple of discolored balls. But they were working fine the day my left front got shortened.
Colin
(Robbie, these driveshafts have the factory original BobD CV boots on them. I took them off the BobD at some 29,000 miles, asked Bob if I could have them, and they have 70,000 additional for a total of 99,000 miles, right? So when these Rein boots give up, BobD gets his boots back, Ha!)