Ok, I've spent the whole morning reading all the pages in this thread, because I have one more question and I don't see it addressed anywhere...
i had one of my carts filled up with .5g of ice cream sativa hash oil. It generated enormous, tasty, and potent clouds on day one, but on day two, same as dankd420, the vapor clouds dropped considerably and i was only getting thin MFLB-levels of vapor.
By this time, I had maybe 60-70 hits on the cart. I figured maybe the .5g would last me 180-200 hits, but maybe I was taking too large hits, or there's more residue on the sides of the cart with the smaller .5g of material, etc. So I figured I got 70 hits per .5g, which honestly, I'm still happy with.
So I take the mouthpiece off, and press the switch while peering in the little air hole. To my surprise, I see an orange glow. "Yup, I guess that means it's out of oil and the cart is empty since I can see the element." I decided to keep heating a bit more, and I did 3 x 6 second primes (is this bad for the battery?) During the 3rd prime, the orange light starts dimming slowly, but the blue LED on the switch was not yet blinking. I figured something must be cooling down the heating element - was oil re-melting off the sides back onto the element?
I took the hit, and YES - thick fluffy vapor clouds as potent as they were on day one. So I realized something - during night, or non-use, I had been storing the pen on its side. Does the oil settle to one side, and stick up there? until I cleared the air tube and bottom hole with a small wire, then ran the prime 3 x 6 seconds, it was thin vapor all around like there was no oil left. I just wanted to be sure that what I'm doing now isn't harmful to the cart and is within normal parameters of priming - I'm not just burning off the last remaining bits and harming the cart in the process, am I?
On an aside, does everyone here agree that a small digital scale is the best way to tell if a cart is empty/near empty or not?