I've been told that, but the miles around here tend to be kind of rough. I live in the mountains, so there's a lot of hill driving, and my wife (the main driver of the car with synthetic) is a stay-at-home mom, so it doesn't see regular commuting duty. It gets a lot of short runs, long drives and everything in-between. After 5000 miles (takes about 4 or 5 months) the oil is pretty dirty.

The oil in my 4Runner gets changed every 2000 miles. I drive it daily to and from work, but it's only 4 miles round-trip, and the rest of the miles are off-road. It takes me about 4-5 months to put 2000 miles on the 4Runner.