I do the same thing! I switch pg/vg levels depending on what I have on hand that day. And now I am starting to lower some of my nicotine levels (Yay!) So, I like to know what I made, if it's perfect and want it the same, or if it needs to be changed. Also, if the recipe calls for a specific steep time, I usually try to add that as well, if it fits. I bought amazing, inexpensive labels on Amazon for essential oil bottles that work so well, fit a 10ml bottle and up, and they are waterproof. They work really well for bottles that you reuse all the time with the same recipe, because they hold up.