If it's been took care it won't be a big issue. Yeah, have to replace drive shafts every once in a while. About $1400 a piece.  Around 10.000 hrs the upper arm pins will probably need replaced and the holes line bored. We had to have 1 done at 5000 ish hrs but it was bought used at an auction. The ones we bought new made it well past 10.000 hrs before needing those replaced.
Just keep them greased and they aren't that much more maintenance and the ride is so much better! Well worth it!