When you say casing -- do you mean engine case, or bearing cage? The bearing cage, rather than the ball-race, is usually the culprit.

There isn't a lot that you can do except to use after-run lube to avoid rust, & limit the amount of time at very high revs. The rear bearings in most 40-46 size sport engines are limited to a max of ~16,000 RPM. They will survive for a reasonable time at that speed, but if you run there all the time (some engines develop peak power higher than that) it is a good idea to keep an eye on them & replace them at the first sign of wear. The bits from a collapsed cage can cause a lot of damage.

If you are going to run steadily at very high revs, ceramic bearings might be a good idea.