both are fine for a snake to live in but tubs are just a lot easier for many reasons. if u like tanks thats fine, but have fun battling husbandry and cleaning. i use tubs cuz husbandry is easy and cleaning is so much easier. i dont think either will effect the lifespan of the snake, i believe the conditions inside of the enclosure will. if an owner doesnt feel like cleaning a big heavy tank every weekend and lets poop and everything sit there then the snake may become sick. and over the years that could effect them.