I've had one 510 atty die after two months, and a 901 atty die after about one week. But I do think that I know what I did wrong with the 901. I "hit" too often, and did not allow the atty enough time to cool down. I am finding that if you puff too many times in a row, with little time in between, and heat the atty up too much - dead atty.
I'm still trying to figure out what the "sweet spot" is for how many puffs, for how long per puff, over how much time, will help keep an atty alive longer. But I do know that a user error in too many, too long, too often, was for me a likely cause of atty failure.