I inspect all bearing on "new" (to me) trucks. I'd have no problem reusing good bearings, but I have rarely found any (the trucks were poorly maintained - cleaning/greasing wheel bearings is cheap, but a relatively dirty and time-consuming task for a shop or owner).
Regarding roller bearings, they are "cool"/strong, but not really a matter of safety on modern roads. If you do not swerve around a lot on country roads, or you do not drive 20,000 or more miles a year, AND, you clean and regrease the bearings regularly, I bet you will never wear out a new set of roller bearings. New seals are not that expensive ($8-$10).
