I actually never completely close it, unless I’m cooking. Once done cooking, I leave it open to cool, clean it, and the leave the lid propped partially open.

It’s still protected from precipitation, but if I close it all the way wasps inevitably build a nest in there. I don’t like my hamburgers that spicy.

But yes, I do this after every use. How much effort is it to just cover it? Why wouldn’t you?