I was taught by my hoary old CFI to maintain 1200rpm and use brakes against power if that was necessary. He maintained that brake fade would not be an issue at taxi speeds, that resultant brake pad wear would be minimal, and that in any event brake pads are cheaper and less hassle than oiled up plugs, valves and combustion chambers.
Likewise when setting mixture in the cruise he always used to say "Fuel is cheaper than engines."