^ mate, it doesn’t matter, just chuck the chain checker away. and put the hose down!
Pretty much all modern decent chains are bushless, even cheap <£5 jobbies, and I’ve never consciously used a bushed chain.
Best I’ve managed on my SS commuter is just shy of 12,000 miles (all weather) on a KMC 510 chain (bushless). It got cleaned twice in that time, and lubed infrequently, normally when the squeaking had been annoying me for a few days too many.
The chainring and freewheel were absolutely buggered and the chain was more worn than you would care to measure, but it still worked, and never skipped. I only replaced the whole lot because the teeth were so worn on the freewheel they were in danger of starting to snap off.
and when it was time to replace, a chainring is £15, another KMC 510 is about £5 and a freewheel is from £15 upwards depending how posh you want, so basically entire drivetrain for little more than the cost of a posh chain.
If you’re running SS or IGH just forget about it, lube it when it squeaks and replace it when it skips or snaps.