Help with 7.5 yr old (65lbs & 52")

Our long torsoed DD7.5 yrs old has a Britax Frontier in my van, and a Britax Parkway in hubby's van. We live in Ontario.

Parkway - I don't have the manual here, as it's in hubby's car with the seat, but what is the max. height requirement? When will I know she is too tall for the seat? If she outgrows this, can we get a Clek, or, does it mean she can't be in a booster seat any longer?

Frontier - Can she outgrow this seat? In booster mode, is there a time when it's dangerous for her to be in this seat?

We want to keep her in a booster seat as long as possible, especially since we take long road trips to Florida. I am still confused as to whether kids can outgrow booster seats, and when it becomes dangerous to be using a booster seat? I see that recommendations are for most kids to be in seats until ages 10 -12, which is what we want to do. Around here though, people take kids out of boosters at like age 7 or 8, and it drives me crazy! We are all about safety in this household!!!

Can anyone help me with these questions? I think she will outgrow the Parkway before the Frontier based on the seats, but I'm a bit confused on some of the specific details.

Thanks, Tiger

I'm not sure if either one has a maximum seated height specified, maybe someone else will see this and post.

In general though for a high-back booster you want to make sure that the top of the booster shell is at least to the tops of the child's ears. The seatbelt fit is going to be your other key thing to keep an eye on. If the shoulder belt is too low, and the guide can't be adjusted to remedy that, you will need to look for a different booster.

The main purpose of the booster seat is to position the seatbelt properly on the child. When a child has met the legal minimum requirements and can pass the 5 step test, they are safe to be using the adult seatbelt without a booster.

ETA: Do you know what her seated height is? That may help with recommendations.

According to the manuals, and I know this is true for most boosters. It is outgrown when either the weight limit is reached or the top of the ears are over the top of the headrest. If they are outgrown by height, then the child can be moved to a backless booster, as long as they're under the weight limit of it.

ETA: selinajean beat me to it and did a much better job of describing it too.

I mentioned the 5 step test before but forgot to link to it. http://carseatblog.com/3966/the-5-step-test/

Just to clarify on moving to a backless booster...

For kids in backless boosters there can come a point where they are safer without a booster. If the shoulder belt is slipping off the shoulder, then it can be a sign that the child is too tall to properly fit in a backless booster - sometimes a different one, or sliding the seat closer to the seatbelt retractor will remedy that, but usually a child will pass the 5 step test when that problem develops.

The other thing to watch for with a backless booster is that there is head support to at least the child's ears.

Also in regards to outgrowing a high-back booster, if the shoulder belt guide is below the top of the child's shoulder than they've outgrown it. The Frontier goes monster tall - many adults would fit it still. I'm not familiar with the height of the old parkway to know how long it tends to last, but the Frontier should last as long as you want her in a booster.