Just a survey... .

I change the oil and filter in my vehicles as follows:

* Lightly driven/antiques -

Since these don't see more than about 1,500 miles annually (sometimes less than 500) I go by time interval instead. I do them twice a year, in spring and fall - always using top quality synthetic and premium filters.

* "Daily driven" -

Both trucks get their oil and filter changed every 3,000 miles, always with high quality synthetic and premium filters. This may be on the over-cautious side but I know it can't hurt and I suspect it might be part of the reason that my trucks both run like new - including the '98 with close to 120,000 miles on it. (The engine still pulls appx. 19 inches of vacuum at idle, indicating a very "tight" engine.)

* Tractors/mowers/power equipment -

Once a year - at the end of the season (fall) before they go into a period of several months of disuse. (I do start each one once every four weeks or so during the off season and let it run for about 15 minutes.) My theory here is that it's good to get the old, dirty oil out at the end of the season rather than leave it sitting in the sump until spring. Fresh oil in them before storage helps keep things clean and well-lubed, so the equipment will be easier-starting (and wear less) come spring.

What do you do?