We're using Easyfits V2 (so not the newest ones) and they didn't come with an extra booster. My LO is 18 months and I don't need to boost them at all. He used to be a mega wetter but nowadays he wees on the potty alot too. I check his nappy about every 2 hours. Sometimes he goes a lot longer though (when he's with Daddy
) and he's fine then too. A bit wet but never leaking.