I'm with Jamvector.
vaping is very subjective so everyone has differrent experiences and opinions. In fact, get 5 vapers together and ask a question, you'll get 17 different answers. These are mine:
I love new cartos and new flavors (yes, I am a flavor ....) and in the last 10 months I have amassed nearly 1000 cartos. That being said, I'm also a bit of a pack rat. I don't like throwing something away that might be useful. I started using cartomizers because I liked the idea of changing flavors instantly. I have several mods, drip tips, whirlygigs and doodads but always find myself back to the KR8 Batteries and Cartos. It's just too convenient.
I use a carto once and put it in a tub for cleaning. About once a month I get ambitious and wash them out, boil them and let them air dry for a week or 10 days.
Then it's time to refill.
I use a sharp tipped 18 gauge syringe (be sure that the point is touching the metal) and fill exactly 1ml. 99% of the cartos take the whole load. If some still seem dry I will drip more juice while poking the batting until it appears saturated. After the carto appears full, I reinsert the needle to the bottom of the carto and draw back a bit of juice till I get air bubbles. This reduces the number of "Slurpy" cartos in the lot.
***A word about syringes*** There is no reason to fear poking yourself with a sharp syringe as long as it's your syringe, Bought New and never used for intraveinous application. The only risk of infection would be due to not cleaning the needle regularly or not cleaning a puncture wound. I bought 100 18ga syringes 7 months ago, gave 20 away and still have 70 in the box. Wash in hot soapy water, air dry and reuse.------if you stab your self more than once in a refilling session you're not paying attention to what you're doing.
Since I spend most of my time at work talking on the phone I have lots of "hands free" time so I usually do my refilling there. So far I have refilled up to 500 cartos in 1 sitting.
With the cost of cartos going down and my large inventory, the dead or unpleasant ones get a quick and unceremonious burial. When the cost for filled cartos gets to about $.60, I won't even worry about reusing them more than once or twice.
OT: I have been toying with a new idea for relabeling them. The labels are 1 5/16 x 1 5/16 inches so I used MS Word to make a template in that size and I'm going to visit some sign makers and see if a) the vynil they use woud work in a laser printer. b) the lettering is cut by computer. c.) how much to make me 10 8 1/2 x 11" sheets in various colors. If it's cheap enough I can buy some, print the flavor on the label and wrap it over the existing label. They might even be reusable. Might be a business opportunity in there.
feel free to PM me or ask any other questions you may have. Good Karma is priceless.