When the outside temp gets in the hi 80's, I switch my units from auto to hi. This results in a more even cooling as the air keeps moving when the compressor turns off.
IMO, the only excessive wear on the fan motor not running on auto will be in the bearings.
Short cycling of the compressor will normally trip the internal overload device. If this happens a lot you could damage the overload to the point it may not reset.
Also, short cycling results in higher than normal amp draw, and this could damage the start cap/device.
