vapeluvr wrote:

Meanwhile, I have man many many Picos (75W and others) that are 3-6 years old, as well as Swag and Swag II mods that are 1-3 years old, and all the battery caps are fine. We call your problem "user error". Learn how to screw on/off chinese battery caps properly and your caps will last longer.

Ok, tell me how. I do not tighten the cap too much, i stop when it see that it makes the contact and the box turns on. The problem could be that i change battery more times during the day because when the batteries get old they do not keep the charge like new ones.
But if i had to buy new batteries every year and throw away old ones to make it last a bit longer i would spend even more.
I have heard other people having the problem with the cap on the Pico 75W and also other Eleaf models so it's not "my problem"
You have many Picos that are 3-6 y.o. and still work because you do not use them. The fact that you have many is the proof; you wouldn't be able to use them simoultaneusly and together with the other boxes you have because you have one mouth only. It's very easy to preserve things not using them.
So you don't have to reveal the secret, it's here: buy ten, alternate them and they will last 10 years :D