After over 400K on the clock my blower fan died. No problem. Replace. Less than 6 months later, it might be dying again.

The only thing is that it died the first time and now and someone is using the car. She always turns the fan up and down depending on how hot or cold she is and when she is settled down, make adjustments.

Question 1: does it make any difference from a physics standpoint?

question 2: does constantly turning the fan up and down hurt the motor?

TIA

__________________
01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow