If the 3880 is any indication of its replacement the 800, simply leave it on. The 3880 in the studio is left sitting for 3-4 weeks at a time, needs few cleanings and is then used to print a couple hundred prints before its left on its own.
The service tech says the best thing is to leave it on.
Since 2011, I think the black change-over valve was replaced a couple of times and it has probably had to be reset a couple of times for non-user parts at the end of their lives but keeps on printing away quite well. I think that the next time it has an issue, it may finally have to be replaced, but that's probably two to three years out.
(edit) I should add that I've had a second-hand 9900 for 8 years now. I had it serviced 3-4 years ago. Though I have to run a cleaning cycle every couple of weeks for after a week or two of sitting, it's doing just fine and all nozzles are firing on cue. It will sit for a week or two then up to a month for my travels and it keeps on printing just fine, though it takes more cleaning than the 3880 just across the room. It, too, is left on though both were cut-off with the rest of my community during the power blackouts a few weeks ago.