my smaller hookahs, i wash out after a smoke. my larger syrains, i clean once a week. when you have 5 of them, i tend to smoke one, then the next, then the next... till they are all used. Then wash the whole lot! the only one I take time to wash after use every time is the new 22" i won - i just want it to last and not rust on me
But I always empty the water atleast... and blow thru the hose as well.