Multiple SD cards for multiple OS's?

[montero65]

So I've got a functional Android build already working, but I'd like to try a few different things as well.  I'd like to give Remix a shot, as well as some of the other images people have posted like TV64.  Rather than re-write my SD card each time, I was thinking of getting a few cards, and each one having different OS so I could swap between them .  I'm mainly wondering about size though.  I know that storage space is needed in addition to any OS images, but not sure how much.  Basically looking for advice on if I should buy 8GB cards, 32GB, or or go up to 64GB.  Obviously, there is a cost difference between these cards, which is why I'm asking for opinions on what size I really need.  Thanks for the input.