I buy extra bottles of my favorite flavors in 0mg so I can dilute as needed, especially in the evenings when I tend to chain-vape but would like to be able to fall asleep before 4 am. I also keep 0mg flavorless on hand for the flavors that I don't use as often (and therefore don't want to buy a whole bottle of 0mg in that flavor). Since I always get extra flavor shots in all my juices, it's no big deal to cut it a bit with some flavorless. I use 12mg most of the time, but sometimes it's nice to have some 18mg for a vape to hold you over when you know you won't be able to vape for a couple of hours. When I have a lot of meetings and I only have time for a quick vape every couple of hours, some 18mg in an e-roll works well for me. Then I easily go back to 12mg as soon as the meetings are finished.
No bottle shall be wasted!!