On my dearly departed Epson 3800 (NOT the 3880), I often left it for a month or two without printing and almost never did a nozzle check.
After I ruined a few prints that way, I decided to get in the habit of regular nozzle checks. Then my 3800 completely dies and I got my P800, and I now do nozzle checks regularly.
Cleaning? I probably did it about three times in the six or seven years that I owned the 3800. On the P800, I will do it if and when a nozzle check fails, but not before.