It has been suggested by clean air store in our community that we leave the fan motor running all the time in order to circulate the air through the filtering system and keep the interior air of our home cleaner. Aside from premature failure of the motor and the expense associated with running the fan all the time, does this option have any other drawbacks or does it make sense from an interior air quality aspect?

My fan runs all the time at a reduced speed. It is called Constant Air Control. Especially useful if you have allergies ETC.