Why does the dust come back?

The average dust for one household is 40 lbs a year. You have two kids. That's four people? And 2 cats. Animals add more dirt. In an apartment which is a relatively small space. I find microfiber is one of the best materials right now, wet or dry. You have a very active house! Dust from top to bottom, then vacuum. In your case, frequently. Just the way it is, for a while. Eliminate pets, it will get better. Eliminate kids, as in grown, better still. Any different, I would have been out of business a long time ago. A word to the wise: don't try to be too perfect. One certain thing in life is that life changes. Houses will be here long after we are gone. Enjoy your family:) Dust is only dust:)