Anna is 6 years old and 45 lbs; Catherine will be 5 in April, 42" and 34 lbs. Anna is in a Britax Marathon. Catherine is in a Graco something or other. Anna's Marathon will be expiring soon, and she has about outgrown it anyway. Catherine has another 7 or 8 months before hers expires. So I have to decide what to do.
My husband thinks we should just put Anna in a booster, and I guess I would be okay with that. But I'm not sure that it's the best idea. But then, while I know harnessed seats are safer than boosters, I'm not sure how MUCH safer they are. If they are 50% safer, then it's definitely worth getting a new harnessed seat. If it's 5% safer, I'm not sure. It's one thing to keep a 6 or 7 year old in a harnessed seat; it feels like another thing altogether to purchase a harnessed seat for a 6 year old.
I'm less okay with moving Catherine into a booster. Even in seven months, she'll still be 5.5, but likely still under 40 lbs.
So, I don't know what to do. I've looked at the Graco Nautilus, the Britax Frontier, and the Regent. (I know they're discontinued, but I think I could find one, and for a similar price to the Nautilus.)
So it seems like I have several options:
1) Put Anna in a high backed booster now, and leave Catherine in her seat. Move Catherine into a booster when her seat expires.
2) Put Anna in a high backed booster now, but purchase a new seat for Catherine in seven months.
3) Buy a new seat for Anna, and when Catherine's seat expires, move Anna into a booster and Catherine into the new seat.
I'm leaning towards either 1 or 3. If there is not a significant safety margin, #1 seems reasonable. If it makes a definitely difference, then #3 seems like the best solution. But then, which seat?
So, I'm putting myself in your hands. Tell me what to do!