What is the shelf battery life of a new Smok device?

Hi,
Because of increasing govt restrictions including the new USPS ban on shipping, I've been stocking up on devices I like and now have 4 brand new smoks {Novo 2 and SMOK NFIX 25W Pod System}.
I assume the pods themselves will keep indefinitely – But how about the batteries, which I believe can not be changed, correct?
How long can I store, without using these, and maybe other, Smok devices without using them and still expect the battery to be good?
One year, two years, how about…

What is the shelf battery life of a new Smok device?

Original source: https://www.e-cigarette-forum.com/threads/what-is-the-shelf-battery-life-of-a-new-smok-device.957681/