Welcome jlittle,
I change mine based more on calender time because I worry about condensation. May or may not be an issue, but I figure if water can build up in the gas tank, why not the engine block ? Plus, it give me more tinkering time with my Yanmar that way. 62 engine hours this year, oil & filter change twice so far and at least once more.
Where are you from, what do you drive ?
Bruce