It seems to vary... could be quality control issues, how they are used (higher volt
mods, holding button down too long and heating them up too much), over-cleaning, etc.
Personally, I have 3 510 atties that have all been in use for almost 2 months so far with no problems, all used every day by 3 different people. We don't let them burn more than 5 secs at a time, no dry burns, no cleaning, occasional blowing out with mouth from the battery side. Incidentally, these are the "newer" longer lasting atties I got from Innovapor. Word got out that they were knock-offs made by a 3rd party company and some people loved them, others hated them. But apparently so many people complained that IV decided to drop them due to too many complaints. Shame too, because they are work horses and I have had no problems. But then, others have used the original 510 atties with no problems too. They are sort of hit or miss it seems.
Others will chime in I'm sure with their experiences.