I tend to err on the side of caution, particularly when my profit margin is on the line. Back when a re-ring job was pretty common practice, there were plenty of other shops that didn't have a problem with installing rings in some pretty badly-tapered cylinders, or even a few that would rebore one hole to correct a scored cylinder. Most of them catered to the used car lot trade, so the salesman could claim his latest lemon had a "rebuilt' engine. I always went for longevity, as I found the customer would tolerate a bigger bill if he could be sure the job had a better chance of lasting a long time. Dad had a saying we tried to live up to- - - -"You can shear a sheep many times- - - -you can only skin him once!" One cut-rate job that ran the customer away was not worth it, because then we would have to find another pigeon.
Doing ring jobs without reboring are a thing of the past, because rings and blocks wear at about the same rate these days, and by the time the rings wear out, the block is beyond the point it will accept another set of rings without a rebore and new pistons. When a set of soft cast rings usually wore out at around 20,000 miles, we could do one or possibly two re-ring jobs before it was necessary to bore the engine. The first rebuild isn't necessary before the 200,000 mile mark on lots of engines, so modern technology and materials has just about eliminated rebuilds anyhow!
Jerry
