Only 6mg now. I started at 18 but was having sleeping trouble, same with 12. A little shocked, I smoked 2 pad. ND winters conditioned me to down a smoke in 52 seconds. For some reason my body needs the lower mg vaping nic.
At that pace you should be buying 24mg and diluting it down yourself with PG/VG. Personally, I find ejuice flavors too strong so I dilute it down to around 18mg. I vape about 5 mL per day at that. Dilution saves me money and makes me happy, it's a win-win!