I clean mine a lot more often...maybe every month or two. I purchased a soft bristled, long handle brush (maybe 3' long) from Home Depot designed for cleaning air vents, and the hoses of dryers and washing machines. I pull them off, flush them with tap water and run the brush through them...you'll be shocked how much gunk gathers up in them in a short time. IMO, if you see any debris coming from the output when the canister is turned back on...you're way past due for a cleaning.