Without having done regular updates on each of the girls, I forgot to record an important milestone. Some might not think this is one, but to us it's a pretty big one. Jie Jie finally grew tall enough and heavy enough to graduate from her booster carseat at the age of 12.5 years old! This happened last September. Technically, she can use it until she is 80 or 100 pounds, I can't remember which, but she was psychologically ready to be out of it, too.
Some parents may have gone with the age rule, but with Jie Jie's spinal anomalies and other physical issues, it was safer that she stay in the carseat. It was a Britax with a 5-point harness system that fastened with LATCH or the car's seatbelt through it securely. I'd never use a booster that relied only on the seatbelt to hold the child and seat in place, I've read too many reports of the seat, with the child in it, being ejected from the car during an accident.
Soon, Apple will use this seat, but at 5 years old and only 32 pounds, she's still in a Britax that goes from infancy to 40 pounds and the only reason I'm switching her is that it's be used to it's max factory lifespan. I didn't even turn her forward facing until she was 3 1/2 years old.