Just today I realized that I'm going to have to, finally, remove the five point harness from my very tall six year old's car seat and use the seat as a high-backed booster. I'm not happy about this. You would think I would be doing cartwheels, as most people chuck their kid's giant car seats as soon as possible to jump for a lighter/easier model, but not me.
For me, for us, the right choice is to keep my children in the safest seats we can manage for as long as possible. I take the statistic that the number one cause of death for children is auto accidents very seriously. Some may say I'm over-protective, or just a big fat worrier, but I'll take it. I've been chided for my desire to use monstrous car seats for my children when it "isn't necessary". But you know what? I don't really care. As far as I am concerned, they are absolutely, unquestionably necessary.
As parents we all take the precautions with regards to our children's safety that feel right to US, and this is one of mine. I also feel like I have statistics on my side here, but again, the bottom line is, we do what works for our own family.
So why, you ask, do I care so much? If the law states a child can be in a booster seat when they have "outgrown their forward-facing car seat" (at least in the state of WA) then why isn't that good enough? As far as I can tell WA state has laws for how long a child needs to be rear-facing (one year AND 20 lbs) and then another law that says how long they need to be in a booster (until they are either 4'9" or 8 years old) but none that specifically states when you can lose the harness in favor of a booster. Not that I would pay attention to it, since the laws are not nearly strict enough in my not-so humble opinion.
If you can, take a gander at this article that a CPST suggested to me when I asked for a good read on why it's safer to have children in 5 point harnesses as long as possible (vs just a booster). The article states that the benefits of a 5 point harness are that:
* The crash forces are spread over the skeletal body over five points rather than three.
* The crash forces are spread to the strongest parts of the child's body.
* Forward head excursion (the distance the head is thrown forward) are lessened.
* The child is secured in the correct seating position rather than being able to wiggle around, lean forward etc. (Sybil's note: as well as slump over when they sleep!)
It deserves to be mentioned that it can be less safe for a child to be in a seat with a 5 point harness if it doesn't fit correctly. For instance, if the top straps are set lower than the child's shoulders then it could cause spinal compression in an accident (info credited to my CPST friend).
Both of my girls are in Graco Nautilus seats (my girls' seats are bright pink and covered in flowers). They were purchased fairly close together, so we had to throw down a big chunk of money for them all at once. Before these seats they were both in Britax Marathon's from birth. Iris's expired around the same time she outgrew it and Eloise's we were able to sell for a little money that went towards her new seat. I have extremely tall children who have/will outgrow the height of the seat far before the weight, which happens to be why Iris needed another five point harness seat after the Marathon.
I would love to rattle on a few more paragraphs about the importance of installing car seats correctly and buckling children in properly, but I'll save that for another time.