3000 gives me piece of mind and about 500 miles leeway in case I'm too busy/ lazy. The older the engine, the sooner it dirties up. I use cheap fram filter and Quaker/ castrol/ valvoline 5/10 w 30. Never pennzoil.
Yeah, in the south that is the requirement. But up here in the north, maple syrup is what they tell us to use, or honey. Once it crystallizes, it ports the intake and cleans inside the motor so well, that by the time your done, you won't have a motor anymore.