Back in the days when the 9-5 had a recommended 10k oil change schedule it was easy to keep track of the miles between service. These days 3000 to 5000 miles between oil changes is generally accepted to ward off sludge.
An easy way to keep track of mileage is to clear the "DIST"- Trip meter on the SID after you finish your next oil change. You can then check the exact distance you have gone since that oil change with the push of a button. Always document your oil changes on paper, but by also using this tip you will have a quick and easy way of keeping an eye on the mileage without digging into your records or relying on your memory.
There is another way of using the DIST function; you can set the distance at 3k (or any amount) and know that when it hits zero you are due for a change. That takes a lot of button pushing. I just clear it to zero and let it count upwards.
3000 miles and I know I'm due for an oil change.