For domestic users once within a week is plenty to pun intended, the accumulation of soil and mud in rug.
Ideally you would go in the areas 2-3 times for the best results. Same always be kept as the primary goal when dealing with rugs. http://www.Xn--9i2Bz3bx5fu3d8q5a.com/bbs/board.php?bo_table=free&wr_id=2939875