Will too-frequent oil changes wear out your wallet or your drain plug threads first?

I have oil and filter changed in my fleet at intervals outlined in the Owner's manual, and adjust for climate and driving as best as I can. Our cars go 30-40 miles each time they're started.

Of all of my problems in all of my vehicles over all of the years, not one would have been prevented by a more frequent oil-change interval. Now if I can just figure out how to keep other drivers from turning or stopping in front of me without warning, all I have to do is look up the proper interval to change head gaskets...