The life of an atty (atomizer) are depending on many factors: if you run it too dry, it may fried and die instantly. If it's wet enough all the time, some e-liquids left some residue, and may gunked the coil, so no one can tell how long it will last. I have 2 atties still woking good (306 LR atties) for 4 months now, with some cleaning. I soaked them in 95% alcohol for a night, shake them to remove some gunk. And left them in a paper towel in the morning, when I got home, they are already dry and ready to use again.
Some people said that dual coil cartos may fried an ego battery, but I haven't got any problem with my ego set using dualcoil cartos.
Sent from my mind using my fingers.