 We have owned our Xterra since 2000 when we bought it new.  Now, just rolling over 180,000 miles, it has never been in the shop for more than a check-up. Routine oil changes and new plugs, wires, and fluids at 100,000 miles is all that has ever been done.  Recently had the air go out, but after ten years and 180,000 miles I have no complaints with the build quality on this one!  If you're looking at buying one used, I would not be intimidated by high miles.  Certainly mine has been super-reliable so far, and I would not hesitate to take it on long trips.  Super reliable!  