Rod and main bolts-replace?

If I was using said engine in a drag race forum, then I would have measured the rod bolt on first assembly and on disassembly. There is a given amount of acceptable stetch by manufacturers before replacement becomes necessary. If you don't know your measurements then I suppose one would have to weigh the factors like, bolt size, piston/rod weights, RPM used and number of passes, and then your best educated guess. I know of regular racers that run a good two years on the same rod bolts with no problems. Ask racers. Just remember that the rods should be resized with new rod bolts.
Replacing main bolts. I'd be using studs. And I would think they'd last longer. Same thing for the main bores. They'd have to be checked for proper alignment after replacing studs.