> those five minutes running a cold engine with no load will be the highest wear rate your engine will ever see

That use to be true in the old days of carb and chokes, where the engine had to run very rich and you got dillution on the cylinder walls due to the overly rich mixture.

But frankly, that isn't true any more with the more precise metering and more uniform fuel delivery systems utilizing computer control and injectors to vaporize the fuel (as opposed to a venturi/choke/fuel jet combination in older vehicles).

The move to electric fans instead of mechanically connected fans also speeds up the warm-up time at idle as compared to older vehicles, where the fan ran at idle, regardless of the temperature.