Hi! Another factor in how much juice you use is your sense of taste. I smoked for 40 years and my taste buds were pretty trashed. I was very excited to try all of the flavors of juice people raved about, only to be disappointed when I couldn't taste anything or it tasted like plastic. I would fill-up a cartrdge, clearo, whatever, taste it and end up pouring it down the sink. Luckily, I was a menthol smoker and found an extremely strong menthol/mint/cinnamon combo I could "taste" (I'm still not sure if I tasted it or if I was just feeling the coolness). It took about 2 months before I could taste other flavors and I still can't taste many of the subtle ones.
There was an upside though: I ended up learning how to drip, so I could try juices without too much waste (an LR306 atty with a Cannon drip tip is brilliant, by the way); and I learned about polypropylene and glass carto tanks, because the one vape I could taste melted clearos and vivi novas. That has turned out to be my favorite configuration.
You're in for a lot of fun!
View attachment 157172