Having our AC intake filters delivered every six months automatically. We have an awkward filter size to find in store. Our intake used to be a floor furnace/heater from way back when that was converted to the air intake when they installed AC. We get this 6 pack every six months so I don't have to remember the size or to go out and buy one each month.

https://www.amazon.com/dp/B07FP5X3JH/ref=cm_sw_r_apa_i_8EA0Eb03GDHFY