4k miles on my work truck (that puts it at about 0% oil life - after just over 3 months) using synthetic but I had conventional only the first 190k.3,000
5,000
7500
10,000
15,000+
I like to run 5,000 miles as it is easy to remember and I think a reasonable use of the Syn oil I run.
3-4k miles on my 84 Cutlass and 83 Caprice depending on how many long trips (commute to work is only a few miles) and the temperature.
I did go as much as 7500 miles in the Caprice once when I was driving it 100 miles a day.