Do I leave the espresso machine On/Off? Answer: Yes.

So lets get this out of the way - for most business owners in most situations the right answer is “set it and forget it - we got drinks to sling” and with good reason:

Reason one: Turning nearly a gallon of water into steam takes time, and there’s nothing worse than having an early AM line at the door only to discover someone forgot to turn on the machine when they crawled in to work.

Reason two: If ya’ll remember your highschool physics - heat expands, cold contracts, and entropy will eventually lead to the heat death of the universe. Can’t do much about that last one, but in regards to the first two - heating up the machine makes everything inside expand a bit and cooling it down makes the same bits contract. The amount is small, but it can lead to all manner of irritating leaks over time. Best to minimize the heat/cool cycles.

Reason three: Related closely to reason two - the various rubber and silicone gaskets inside the machine don’t take all that well to being heated and cooled over and over again - they crack. Eventually your technician is reenacting the old cartoons where a Trademarked character with Mouse Ears is trying to stop a dam from bursting only for more holes to appear each time they patch one.

Those reasons aside, the on/off switch has an “off” setting for a reason. Reasons to employ it include but are not limited to:

1. The machine is producing steam, smoke, or flames in a quantity and/or quality that is frightening the customers, the staff, and (most importantly) the health inspector.
2. The machine has a leak and it isn’t clear if the morning will bring a manageable counter puddle or reason to build an ark.
3. The entire staff, on urging of a bedraggled man in a beard, embark on a perilous quest to litter by dropping costume jewelry in an active volcano. Or if everyone’s just going on vacation for 3-4 days.

In short if all is well, probably best to let it run so long as it won’t be unattended too long.