(Crud- Forum glitch and I lost my long-winded reply.)

My rocket engineer friends unanimously agreed- don't touch the bearing until it indicates (noise, etc.) a need for service.

Modern bearings are marvels of engineering. Unlike the bearings many of old-timers remember, modern bearing seals don't leak, don't allow dust and other contaminants in, and the grease is good for 17,000 hours under industrial use. All under industrial loads of ~2,800 pounds of force and abusive test conditions.
As long as we don't directly spray the bearings with a pressure washer, a modern sealed bearing of good quality should a "lifetime" part. A low-quality bearing run under water and hit with 2,500 PSI water stream may be a monthly replacement.

Bearing design is precision science, well beyond my ability to understand. Here's a Google link if you want to see for yourself:

Ball and Roller Bearings NTN Americas

I can't post links yet so just Google it.