I was involved in a discussion about a 1980's pumper with 15,000 road miles. The Chief stated that the pumper was still cherry because of the miles.
I stated that you can't use road miles as any kind of indicator for an engines condition, ear & tear, etc.
I know alot of shops, depts use a formula of; engine hours x 45 = actual road miles.
Let me kow what you think about this topic, formula or any other formulas.