I don't know if it's because I can actually watch the juice level drop while I vape but I am noticing that I go through a lot more juice quicker when using the ViVi nova or Vision stardust in comparison to just a boge cartomizer. On a filled boge cartomizer I would average around 3-4 mL of juice per day on top offs. I'm seeing myself go through 5-6 mL now with the two wicking tank systems. I don't feel as if I'm taking more or longer draws of the vivi or vision. It feels like drop for drop I'm getting more out of my juice from a cartomizer v.s. a Vivi. I don't know if all of this is in my head or anyone else has experienced this.