Hi all,

I'm coming back to the US for a visit and need to decide whether to use the chance to buy a new seat for my DSs.

DS1 is 8.5 years old, 60 lbs and 52 inches. He is at the very end of the harness in his Frontier 80 (? I think it's 80).

DS2 is turning 6, 40 lbs and 44 inches. He's still in his Marathon.

I need to either have DS1 use the Frontier as a booster and plan to replace the Marathon when DS2 grows a bit more (e.g. at Christmas when I'm coming back to the US again), or replace the Frontier with a Frontier 90 (?) and keep DS1 harnessed for longer, keeping the Frontier 80 for DS2 when he comes out of the MA.

I just don't know the data about how important it is to keep DS1 harnessed v. switching him to booster mode. Is there data about this? He is a pretty calm kid and uses a Britax booster (with that anti-submarining thing) when we're in the US because I was being cheap and didn't buy a Frontier to keep at the grandparents'.

There are no harnessed seats for big kids here in the UK, so I have to make my purchases when I come home.

Thanks in advance for the help!

Jess in London