I’ve run into dive shops in the Keys that won’t fill the older aluminum tanks. Think it’s mostly because they have so much business, they can refuse. As for the 72’s. I know several guys that still use them, and am starting to think about picking a couple up myself just because of the weight. Currently using hp 119’s which I love, except for the weight. I still have a ’94 aluminum 80, and still use it on occasion. I haven’t had any problem, yet, having it filled.