For all of you who use these, how long are you getting before topping off? When I vape them, as soon as I see the top and sides getting dry and pulling away from the plastic, I figure it's time to refill them. But when I do ... I only get a few drops in before it starts coming out of the bottom. If I'm not careful I flood them. But I know I've vaped more than I put in! How do you know how long you can vape them before they need to be topped up? Most of the time I get real good flavor but occasionally I get like a dry hit coming from them and the only way to get rid of it is to put a few drops in. Are they kind of a two-week clearo and then throw them away even if they still look fine? I know they would have a certain kind of life span but ... am finding it hard to tell because ... well ... they look okay. Is the dry hit thing a hint that it's time to throw it away? I'm not as sure about these as I was at first. Because they take so much juice, it just seems like you might be wasting quite a bit when it's time to throw it away.