I leave my saw switch on. (I have a foot pedal). But even so, I vacuum the saw switch regularly and work it every once in a while. The reason I do that, I have a remote switch for my shop dust collector, means I leave the unit's switch in the on position. Even so, it quit working once. The DC would not start even with the remote. I cleaned the unit switch and blew it out real good with the compressor and exercised it switching it on/off and it started working again. So I believe, even though it is left in the on position, it needs to be clean and exercised routinely. Just my experience, not to be taken too seriously.