I've been thinking about boostering DD1 full time this fall. She's already in a frontier85 but for some reason its never occured to me to just use the frontier as a booster. It's probably in my head because its the first higher end carseat I bought and I bought it to harness DD1 longer not to booster her at 5. She'll be 5.5 this fall and was 49lbs 49inches in April. I really have no reason to keep her harnessed... I was waiting on her being able to buckle her spare booster with out hassle and she's mastered that. She's mile ahead of her age maturity wise. Sigh. I'm pretty sure DS will get some use out of the frontiers harnessing power lol He'll probably need to be harnessed close to 7 Anyways those who have Frontier85s did you transition them into boosters or buy a designated booster?