[stlcdr]

One other aspect to consider is the inconvenience factor. In the rare situation that something breaks, the binary tree now selects between do you have warranty or not? If you don’t, they order the part, put it in, you open your wallet and you are on your way.

If you have warranty, now before anything gets done, is the part or work covered? While you are waiting on that decision, you have no car. They come back with it not covered, because of some obscure clause (or just because). Now you have to fight. Then they say ok, but…they need to see the broken thing to determine if the failure is due due to some neglect. The find out you painted a bolt under the hood, or put in a different floor mat. Well, that changes things and warranty denied. Now you have to argue that decaf coffee in the cup holder doesn’t have any effect on the perceived failure mode. Two months later you might be able to get your car back.

Personally, I don’t have the time or inclination to go through that.