"He who marches out of step hears another drum." ~ Ken Kesey
we used to turn it off on the weekends but M&R recommended leaving the full air system on unless it's an extended period of down time. So our chiller never get's shut off much like a refrigerator, and we never have moisture at the press. They barely use any power so it's not even a concern there. I thought maybe it would extend the life span, but honestly, if it's running all the time, it doesn't have to work as hard every day, or after a long weekend, trying to draw moisture out of the air system. "Supposedly", it can take up to 8 hours to actually have a freshly turned on chiller at it's best efficiency on your system, I don't know how accurate that is, but a couple techs have told me that over the last couple of years.