What is it for? I would use a life jacket for boating activities or maybe even if we would be on a dock a lot (at a lake). For anything else, swimming, pool, ocean, I would probably use nothing. Most pools won't let you bring anything anyway.
We had DD on a boat at about 22months in a life jacket. It was a little constraining, but that's better than falling in & drowning. I don't like water wings, I think they are useless and even dangerous.