Its been just over a year for my wife and I. We started out exactly like you with a couple of ego kits, they were 900mah batteries and CE4's but they did the trick for a pack a day smoker to 0 ciggs a day overnight. I started to dig into how attys work after I received my first metallic throat ripping vape off a brand new head.
The ego batteries didn't last long and once I started rebuilding those CE4's I needed more consistent power than the ego's can provide. Bought a couple mechs (KTS+ and K100) out of fasttech along with a charger and batteries and marched forward in increasing my vape quality. Found the protank, learned how to rebuild them and since then we have had nothing but top shelf vape quality and still using them protanks to this day.
Now I have enough wick and wire to last a lifetime, couple Provari's, couple dozen PV's and a army of protanks of all sizes. I didn't bother with PT3's since rebuilding them with the dual coils is a nightmare and rebuilding them into single coil units takes DualCoil right out of the PT3 and I have single coil with my protanks so why spend the coin on PT3's?
Bottom line is that its not the money saved by rebuilding your attys, its the enormous change in your vape quality but to get yourself setup with regular mech or mod, charger and batteries probably land you around 100 bucks and its a better investment than rebuying those ego batteries over and over again cause they crap out so quickly being the most knocked off vape product out there.
Google and Youtube are your new best vaping friends.
got genuine joyetechs.dunno if that matters or not.