1/25 1973 NYPD patrol car

A lot of times it's based on mileage.

I've worked at a couple of places with sizable fleets.

One place was 100,000 miles and they were strict about it.

One of my company vehicles got replaced at 86,000 because it was "close".

I've also seen the "overlap" of new and old paint schemes a few times.

That also depends on several factors, like- is it cost effective to repaint a car that's going to get replaced in 30,000 miles.