Welcome to 4x4wire Toyota forums!

I've never had to replace any suspension rubber on a Toyota until being beyond 220,000 miles, and only then with it being specific worn pieces, with the other rubber in the suspension still in good condition...

It seems to be very long lasting material, so at 120K I think you are fine...

The only thing to watch on the rear axle is the rear axle seals.. Some have had problems with them leaking...