Unless he's into hardcore wheeling or does something stupid, he should be fine for some time. Then he can beef it up as time and money allows. I actually think you have less chance of breaking stuff with a 37 than a 35, given you don't push the 37 to its limit. When a 35 is at its limit, you'll likely need some good amount of throttle or rock bashing to go through. But with a 37, you can more easily climb over an obstacle and move on. Basically, with a larger tire, all rocks and obstacles all of a sudden become smaller, easier. Easier obstacle = less chance of breaking.