We usually scale our dirt cars every week.... I've been saving up some old Ford flathead heads to use in the seat but it will still take another $200 worth of lead to mimic my fat posterior.
I have looked at and thought about buying scales many times over the 45 years I have been racing but never have. I am not a “tool borrower” either so I have never scaled a car. I’ve never really had an issue setting up my cars without them but it sure would be nice to have a set.