A bow with frets won't last for nearly as long as a sound bow, but if the back is ok it should shoot until you can make a better bow. My first serious bow (red oak board bow, dimensions from the back of TBB IV) had two bad frets by the center, but it lasted a long time. It did pop a splinter on the edge near the frets, but it was nothing TB II and braided dacron couldn't fix.
Russell, did you get your signature phrase from the Rangers Apprentice books?