Our WaCo puts orthophosphate in the water to delay further pinhole leaks.
There's probably a break-even point between patching one hole at a time and replacing whole sections of pipe.
See if you can find trends for this in your area on the Internet. It will let you predict the probable future for leaks in your area.
One new leak per month probably means replace whole sections.
One new leak per year - dunno'. Are you paying for labor or is it DIY?
Years ago, we only had one leak in the pipe that goes under the slab and had the pipe bypassed, but right over there in Vienna, VA they are having several leaks over several years.
Unbiased sources for info on this might be hard to find. Your WaCo would probably understate the problem, and plumbers may overstate it. In person, I'd ask suppliers of piping in your area if there has been a surge in demand for certain types of pipe, and why they think it is happening. And is it getting worse or better?
In our area it made the newspapers, and utilities think twice before spinning info fed to a reporter.