I have a 2004 Alpenlite with about 50 to 60 thousand miles. The 5er is still rock solid, but since they are anything but light they can be hard on suspension components.I would replace all bushings with greasable fittings and check the brakes. While you're there rotate each wheel to check the neverlube bearings for smoothness and proper adjustment.
My experience with my 6 year old 235/85/16 Michelin ribs has been great. I just removed them from the 5er and measured the tread depth after 50k miles. They range from .366 to .396 (avg 3/8")and will be put into service on the back of my dually.There are no sidewall cracks and only a few scuffs so I'm sure I'll get great service out of the remaining life of the tire.
The problem is do I get 4 more at $1260 or 4 Bridgestone duravis at$948...