Miles depends on a lot of factors, the biggest is wheel offset that creates leverage against them. A 12 or 14" wide wheel is harder on bearings and ball joints then an 8" wheel.
There are measuring tools for it, however most do the shake test. Jack vehicle up, and move top and bottom of tire in an out (with hands) to check for slop in bearings or ball joints. If the tire has movement one of this is loose/failing. Usually as ball joints get bad the tires will wear uneven and when the test (above) is done you will see movement in the ball joints.
