Probably a lot of folks are looking into DIY liquid now that the deeming regs have dropped. If you are considering DIY liquid as a strategy to protect your vaping long term, here is what I would suggest for the hesitant potential DIYer intimidated by the complicated recipes and procedures discussed here on ecf:
1) It really all comes down to the base. Go look at nude nicotine dot com or wizard labs or similar and see how base nicotine is offered for sale. You choose your mix of PG and VG and of course select the strength. Laying some nicotine base by in the freezer for long term is a key part of readiness. Even if you aren't yet ready to make the DIY leap yet, this step is crucial.
2) The first vendor I listed above has more expensive options for long term storage including argon gas and amber bottles; get these if you can afford it.
3) IMO is it not necessary to go right to the 100 mg/ml strength right away. Consider a strength that is divisible evenly by your preferred strengh level. Say you like 9 mg. If you got base nic at 36 mg, you simply add one part base and three parts VG/PG to get 9, since 36 divided by four is 9. Nevermind those who would make elaborate calulations to accommodate the flavoring -- back off a tiny bit on the VG/PG is you like. I like to ignore it. Note that working with 100mg/ml strength base requires gloves, eye protection, etc. At 36, you be careful and wipe any base that you get on your hands. Obviously 100mg/ml makes more juice for less volume, but no need to jump to the 100.
3) Buy concentrated flavors rather than trying to mix a complicated recipe using a large selection of individual flavors. These are complete flavor recipes/combinations you simply add to your nic base once you have diluted it to your target strength. Using these concentrated flavors pretty much eliminates the complicated "10% of this and 4.5% of that" to "dilute your base to desired strength, drop a few drops of flavor in till it tastes good. Some vendors of concentrated flavors include mom and pop vapor dot com and nude nicotine dot com. Both have great recipes.
4) Taste and enjoy unflavored juice! before adding flavor, try it unflavored. VG and especially PG is sweet. Down the line, unflavored may be all we have access to. Not so bad!
The stash of bottles you have laying around will get you started for materials. You can upgrade to better "lab" equipment later. Good luck!