Is it good practice to rotate the use of your attys on a 510, or would it not make a difference if I just use the same one til it quits or until I have to take it out of action for a good cleaning? I hear a lot of people are rotating them, but it might be more of a pain for me... If you rotate the use of them, how do you do it to keep it "evened out" so one doesn't wind up forgotten with juice drying & clogging it up or something?