I find myself topping them off a few times during the day. I use the X2 around the house, walking the dog and while driving and hate to run out of liquid. I also use them for testing liquids, I'm still looking for the ultimate combination of flavor and vapor but SI RY4 is doing a really good job right now, because the are so easy to clean versus a carto or a CE3. I've also found, that for me, vaping just a few drops on an atomizer to test flavors just won't work well. What tastes good for a few drags can get to be boring or downright distasteful over longer periods so a clearo, with its capacity, makes for a much better test. Overall liquid consumption, here, is about 4ml per day on average and a clearo or CE3 makes it easy to keep myself well supplied.