I'm too lazy. I always just let battery-replacement be the odometer reset. Besides, components and tires need replacement at different times so using the odometer as your only source if you care about miles per part isn't very accurate. If you use the same computer on multiple bikes, you can't track anything cumulatively except the total miles for those bikes.

Use a log like bikejournal.com and track whatever you want on a calendar year basis. It willtrack lifetime mileage for each bike.