You could swap out one side of the axle with a rebuild, but if you're going that far might as well rebuild both sides and just swap the whole assy.
If yours are worn, I'd keep them on the car and deal with the noise and vibe until you get a chance to rebuild the other set. That or buy 2 sets, one to swap on right away and the other to rebuild and swap out shortly thereafter. I just exchanged mine again this weekend as I'm refreshing the steering and suspension components, so now I have a spare set again I can rebuild in due time
My original set lasted ~110k miles. Second set used from Erie had 56k (R side) & 82k (L side) miles, and the 82k one lasted another 40k miles before boot failure. The 56k set (now with 106k miles), boots are still intact but passenger side idler bearing was starting to get sloppy. In other words, these axles last about 110k miles in my region - this will give you an idea how far you can push it.






