Ring slings are great for all ages. I've used one for DS since birth, and now he's big and heavy but I still use it. They're easily adjustable and no need to worry about different sizes. So many different ways to carry bubs in them, too. I used to have DS snuggled in it to sleep, then sitting up like a little joey facing out, and now I use it like a hip carrier or piggy-back style. Mine is home-made, so I put pockets in the end of the "tail" so I can take everything I need for a short trip without needing an extra bag. I love it! But remember - keep baby high and tight so it doesn't hurt your back.