In all the years I have welded, I haven't bought or leased a bottle of any kind for thirty years. I buy a bottle contract that cost 100-150 dollars for the bottle first time plus the fill. Then just trade the bottle when it is enpty. At the end of five years if I don't want the bottle anymore I can turn it in and get my money back. If I do, they just extend the contract with no extra expense. There is no use requirement or time limits. Due to a recent move, my new contracts are only a couple years old but before, some were over twenty years old and I got the money back for all of them.So for the price of one bottle, you are assured that you have current bottles and some recourse if they are leaking.