My garbage bottle is labeled Watermelon...which is the first bottle I acquired. It was previously a happy little bottle of..you guessed it...watermelon niquid. It has since become a bottle of watermelon raspberry peach RY4 tobacco blend. I have sucessfully moved on to bigger and better things, like using fresh niquid that isn't mixed with every wasted flavor from my nearly depleted carts. I still have said watermelon bottle, but i've stopped collecting in it, and don't plan on using it. I realized...this stuff is cheap as all heck (<---unsure of forum language restraints).
If you must reserve your leftovers...go for it. My advice: Purchase a large bottle of your favorite indulgence, and stash it away (large being the cheap word). Tap into it on a "need to vape" basis, when all your money and juice has dried up at the same time. When more is acquired, stash it again. Unbeknownst to me is your money situation...but I'm a lowly janitor at a hospital; not exactly rich (on the other hand, great health insurance.) I still can choose not to give in to the watermelon garbage bottle.