I alway calibrate my electronics with one or two drains at first. I drain it down to 10% or so, fully recharge and then do it again. After that I do it once every few months. Even Apple recommends you do this.
Otherwise, I tend to plug mine in whenever I'm not using it. Lots of small charges are much easier on a battery than a few deep drains and recharges.
Google it and you can find several articles on it.
Oh, I never drain it to zero. I've had a couple of phones where I accidentally did that and actually bricked one of them. It never came back. It was older and I think it just gave up the ghost with that drain.