I have flies everywhere in my home and can't get rid of them. I change cage regularly, but the flies keep coming back so much

The rodents themselves don't attract flies. You say you clean their cage regularly, have you considered doing so more frequently?

The type of fly will determine how to get rid of it. Most flies will disappear if you can dry up the environment, which is challenging in the Northern hemisphere as it's wintertime here.

Some flies show up inside due to eggs laid for the winter hatching out in a heated interior.

Until you can determine the type and source of the flies, probably your best bet for control is one of the old fashioned flypaper strips hanging over the cage.

How often is "regularly"?