Absolutely correct! I keep a couple extra filters available at all times. The new washable one's cost more but last longer and seem to work better. If you change/clean the filters, the airborn dust is kept to an absolute minimum. Better than recycling through your lungs.

: Sounds like a fan / filter box, not a dust collector. A prop fan will work,
: but with loaded filters you probably have 1/2" of static, and the
: prop fan drops off in airflow pretty quick. An airflow rating by itself is
: of no use at all unless associated with a static pressure. Your "1250
: CFM" is most likely "1250 CFM free air" or at 0"
: static. And a prop fan's curve drops off real fast at any pressure,
: prob'ly stalls at about 3/4".

: A forward curve double-width fan out of a recycled furnace is a much better
: choice. But hey, if it's working for you, great! Keep the filts clean and
: it'll work better.