Video boroscopes and laboratory oil analysis are now relatively cheap,
but rebuild labor is more expensive.

For flat tappet applications maybe turn attention to how to inspect with a small diameter head video boroscope with minimum teardown, like maybe a tapped inspection hole that can be closed with a plug.

Lab oil analysis on new oil, then at 500 miles?

For large expensive tapered roller bearings “break in” for industrial applications
Torrington used to advise using a heavier, higher viscosity oil
pre-warmed to 30 degrees above expected operating temperature prior to initial start,
then changed at 48 hours.