Anyone out there adhere to the "new rig every six year rule?

That sounds like a salesman rule for suckers. The way they make money is to keep you in payments as long as possible. Continuously dumping money into a depreciating asset is a bad investment.

We're on our 4th tt in 11 years only because we outgrew the previous ones or I got the itch for something nicer. Bought them all slightly used(except our current one was new) paid cash and made money on the sale later.