Hey everyone, I just purchased my Provari a few weeks ago with some attys and like 8 carts for the attys. I was always vaping regular analog style units that used only cartos, so the whole atty/cartridge thing is kind of new to me. How long do these cartridges usually last, and how do you know when it is time to change them? I started getting some hard particles near the mouth piece on the batting, but I assume thats just burned batting, and I cut it off with a scissor. I have been using the same one for nearly 3 weeks, and am just wondering how I know its time to pop in a new one.