FWIW, I got caught between a new heim bearing and a race, so I have performed an informal test of how long the bearing will hold up once it starts to go away. Mine got three rides on it after I discovered it was loose, then I went to E. Washington and rode the Desert 100 with the worn heim. It held up just fine to 100 miles of endless whoops. Upon removal I could see where the race had been pounded very thing, but the swingarm was undamaged and two plates that fit to each side of the heim were intact. This information comes with the typical disclaimer, but IMO if the heim is a little worn and you must ride before replacing it, it should hold up.