It really is dead easy once you have the calculations done of how much nicotine you need. Everything else can be done by approximation (flavors and bases) i.e. if you have 72vg/28pg vs. 70vg/30pg who really cares?

For instance, I make 60ml bottles of several different flavors at a time. To make a single 3mg strength bottle (I'm stair stepping down the nic level to get off nic eventually), I would add 1.8ml of 100mcg strength nicotine to an empty beaker. I then fill the beaker to about the 10ml level with flavor(s) so about 8.2ml of flavor give or take. I then pour that mix of flavor and nicotine into an empty juice bottle and fill up the remaining space in the bottle with VG (I like max vg juice). Put the cap on and shake and bake baby. It's that simple. No scales, no elaborate measuring, etc. If I want some a thinner juice for a pod style device like my Smok Nord, maybe I fill the juice bottle about 3/4ths full of VG and the remaining with PG by eyesight giving me an approximate 75/25ish mix.

Like I said, since this is just for me, I don't really care one bit if I end up with a 80vg/20pg mix or 85/15 or whatever so long as I have the proper amount of nicotine for my desired strength.

From there, it's just playing with different flavors and percentages to find out what you like best which is most of the fun. Yesterday, I made five 60ml bottles of max vg juice in about 10 minutes. How much would that have cost me at the vape shop?! Yet I did it for probably a total of $2 at most, in materials and very little hassle.

I bought a kit from River Supply when I first started DIY and quite honestly, I've yet to use most of that kit outside of a small beaker and a couple of the 5ml syringes. Everything else is still new in the tub it came in. Don't over complicate it.

Finally, I know a lot of people like the chubby gorilla style bottles like most store bought vape juice comes in, but I really don't as they are only good for a few refills at most, then you'll develop creases in the bottle from you squeezing it and those creases can leak. I've since switched over to those skinnier bottles that are more opaque and a little softer plastic. They are made much better, the tip can be removed much easier than the chubbys, and so far, I've yet to have a single bottle develop a crease let alone a leak.

*Edit. These are the style of bottle I use. https://www.amazon.com/gp/product/B07XGDXD37/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1