Vehicles on hand:
1976 Chevy 454 1 ton dually w/ over 345,000 miles
1979 Buick wagon with Olds 403 engine & over 191,000 miles on it.
Oil gets changed at 3,000 or less. Oil & Air filters also. Cheapest thing I can do to get a very long life out of my vehicles. Auto parts store takes used oil.
225k on our 97 Escort and almost up to 200k on my 94 Golf.
same deal- change oil every 3-5k.
Bingo !