Assuming that you are satisfied with the device, I usually recommend maintaining a supply that could hold out for at least a week.
Why 7 days?
That would be roughly the length of time it would take to receive a replacement from a reliable dealer. If your preferred dealer(s) take longer to ship, then adjust your supplies to compensate.
When it comes to equipment, it all depends on how you use your gear. If you are a heavy vaper, you will undoubtedly go through juice and atomizers quicker than an occasional vaper. If you are just starting out, you may want to hold off on buying 500 of each component. It would suck to be stuck with a crate full of parts that will only collect dust when you switch to using the new UberUltraSuperMega Vape 6000
I test each battery and atty upon receiving it to ensure that it is not a DOA. With the 510, I keep a total of 4 batteries. Two batteries for rotational use (i.e. one charging, one in use). I keep a single atty for use and a five pack in reserve. I leave the backups alone for the most part. Until one dies, I don't touch them. Some people rotate using all of their equipment. Since these devices have an unknown lifespan, why risk having reserves that bites the dust the same time as the main?
If any part were to die, I would have a spare which should last long enough for a replacement to arrive. Even in the event of a mass-atty-suicide, I doubt that I would be without a PV before a replacement part could arrive. Attys generally last at least a month, with some lasting longer. I have yet to run into or see one that lasted less than two weeks with proper use. Bear in mind though, acts of nature and the occasional act of incredible stupidity happen. I've left PV's at work, dropped them down stairs, and even crushed one in a car door. My friend dropped her's in the toilet once. Wierd happens, plan for it.
When my supply of juice (whatever flavor is my current fave) drops to 30ml or less, I place an order for around 50mls. I go through roughly 10ml every three days. Since I found an excellent deal on juice recently I ended up picking up 600mls of my favorite. Since you're still in the "experimental" phase, I wouldn't recommend that. There are many places for juice, each having multiple flavors. Finding one you like may take a while, and there's nothing to say that you won't get bored with it after a few weeks or months.
Keep track of the average lifespan of parts as you use them and you will have a better idea of how many parts you will need to have in reserve. Keep your eyes open for sales, discounts, and special deals.
I guess the best advice is to not overdo it. I spent far too much money on an excessive amount of spare parts for PVs that are now mostly obsolete in my eyes. The industry is changing nearly every month. There will be newer and better devices eventually.
Good Luck,
Tinstar
