Dumb iPad question

My wife’s iPad has the “smart cover” which turns it off when closed (it is supposed to, but like a refrigerator light, no way of knowing :smiley: ).

She turns on the airplane mode whenever not using email or going online, to prolong the battery charge. She uses the iPad mostly to read Kindle books.

Question is, if wi-fi is turned on, but the cover is closed, does that make any difference in battery life between charges?

I assume it makes no difference, but no way of knowing. If so, then she only has to turn airplane mode on when reading books. Right?

I’ve only had my iPad for a couple days, but my iPhone gets my email while it’s off. So I assume a turned-off iOS device will use WiFi from time to time. How much of a difference that makes, I can’t tell you.