Hitting a certain number on the odometer is not a good reason to start using high mileage oil. HM oils are designed to address issues that eventually happen to nearly every engine as the miles accumulate: noisy on startup, oil consumption, seeping/leaking engine seals, etc. If your engine is showing these symptoms, a HM oil is likely to help. But if your engine is still running fine on non-HM oil and shows no symptoms, just keep using whatever has been working for you. My Tacoma has 156,000 miles and I have no intention to use HM oil until there is good reason.