Well, we have three cats and a baby boy, all in
a hopelessly overstuffed Manhattan apartment.
In a decade of shooting and processing film in
this space, dust has never been a problem for
the negatives.
I tried doing three once. It worked, but NEVER AGAIN! Too much stress and hassle. I can do two OK, as long as I stagger the times. I stagger one tank to be five minutes behind the other, and let one batch of film sit in water after the stop bath. Once the second tank catches up, I do the fixing step for both tanks with the same clock. During development, I usually miss one agitation cycle this way, but I make up for it by adding an extra one later.