Long story short. I bought a truck and i'm replacing the brake rotors, calipers, pads because they are bad. Should I replace the wheel bearings while i'm at it since their already out? What is the average life of wheel bearings and how much should they cost (without labor, since i'm doing it myself).
to the best of my knowledge, you don't really need to if they are original, in good condition. the thing is, can you check and verify the condition of the wheel bearings? just because you are taking everything else in that department out, shouldn't mean you have to replace the bearings as well. BUT, if you want, if the truck has high mileage, by all means go for it. after everything's done, you might want to do an alignment job.
Are we talking old school wheel bearing or hub assemblies? If old school bearings then in theory if they are fine just regreasing them and putting in new seals should work. Thing is I get your logic. Do them too since you are in there, button the thing up, and call it a day. If we are just talking old school bearings, in and outers, it should not be too costly. I am leaning towards saying yes. Hub assemblies on the other hand can be costly. Those I would probably not do.
