Call your local suppliers to get info on what is allowed for non commercial rules etc, etc.. I purchase my bottles. They only allow up a certain size for non commercial use. After purchase I hold on to my purchase receipts. Al
Make sure you keep a copy of your lease with whoever you sign with. I've been arguing with AirGas for fifteen years about a bottle they claim I have that I never had. I'm with Praxair now, but none of them seem to be very good about keeping up with bottles.
Well 25-30 years ago in Texas I bought what airgas called lifetime lease bottles the carbon copy recipes are long gone.
In Texas and Arkansas I exchanged them no problem usually from the delivery truck when they were local to me.
They didn’t seem to care if the neck ring was marked or not , seems they do here in Cali I got my 75/25 exchanged here and they charged me again for the bottle, so I guess I’m screwed when I need gas. The Airco is a120cf oxygen , with Airco on the ring.