I typically just turn it off during the height of winter. We have to add humidity during the winter months for comfort, so no sense in paying to take it back out.
During the summer (and especially as wet spring turns into warm summer weather), 30% and let that baby crank.
My guns and I both live in the basement, as my office is down here, so I'm able to keep a pretty good eye on everything and it seems to work out well.