Here is my current setup. I'm a little bit addicted.
My last order was about 20oz of various flavors and sizes and enough to make just me, about 2 years worth of juice. But I find I'm loving certain flavors and going through them quick so I thought, screw this, I want tons of the regular stuff. So I do up a list of flavors, 8oz, 16oz and so on and I'm all excited and ready to go and then it dawns on me. I'm looking at enough concentrate to make me almost a decade of ejuice. So I cut the order down a tad. But the other factor, like everything in life, the flavors will degrade over time plus PG is only good for 2-3 years so I'd be pouring a lot of it out down the road. My eyes are too big for my stomach.
I know the feeling. I live in a small town in Arkansas. I started for myself and I had too many flavors I wanted to try, and too many combinations. I used this subreddit to start a recipe book to experiment and tweak each flavor I tried. I opened up a small brick and mortar shop in town. Your advice is noted. I wasn't entirely aware of the shelf life. I go through this stuff pretty quick, but there are flavors sitting in the shadows begging me to make them into something great.