If you are going to put the Bowman ring in Then I would do it now. I ca'nt tell you how long the Engine would run before you would have to replace the original ring. Maybe someone has some hrs loged to give us an ideal how many hrs before you will have to replace the ring. As a rule you would have to hone the cly and maybe replace the cly if it has too much ware. These are throw away parts at that time. My question is are you having any problem to warrant changing the ring out.