My bad.
I didn't write it clearly.
I meant my "circulation" will turn off all times and I just turned it back on and on. I needed stronger AC wind from the blower especially in the SUMMER. Did you feel/notice that when we turned on the "circulation" button no matter at LO, MI, HI speed ....you'll feel that the wind is maybe 5% stronger??
For 92@almost 70K, my blower motor works as new. Always quiet and smooth even in the really cold winter. I always try to keep the interior away from dust and I will roll up all windows if I'm going to pass by some construction areas.
I agree with Beav.....feel stuffy if the "cir" is on for a long time. So when I drive cars with no auto climate control...I will recirculate the cabin air myself.