A friend of mine has an iPad that she uses only once a day for about a half hour.
I told her to turn it off completely in between uses to conserve energy - no point having the device run in standby for 23.5 hours a day. (So no standby, but a real "swipe to turn off" shutdown.)
I'm not completely sure whether this is correct, though. Is this the optimal way to go in terms of optimal battery lifespan? Battery life (i.e. the time until she has to recharge it again) is secondary, we just want to preserve the battery for as long as possible.