DD1, ( now 11) at around 3 yrs old and 30lbs ( uhh maybe 28-29 lbs) she rode in a cosco high back in booster mode for a couple of weeks because she was too tall for the harness, the other combos available at the time with taller slots were the Century Breverra and the Evenflo 2-in-1. The Century didn't come close to fitting my car ( or most other cars) and I had to order the Evenflo through Pepboys. During the wait for that seat she was in booster mode if for some reason I couldn't borrow a car that the Century fit in. Then at 4.5 yrs she was again in a booster while we waited for the Futura to finally hit the market. Once the Futura broke we were again in a booster for about 6 months when she was about 7 yrs old until I could get my hands on a Husky. (the wait list was soooo long) She was never really a very good booster kid until around 9 yrs old. Now she is 5'2" and rarely needs one ( low seat backs and long trips), but I wish she did because she is not a very good seatbelt kid.
DS ( now 8) was in a booster once a week for about 12 weeks when the mom who picked him up from school for me had surgery. He was about to turn 4 at the time. He did ok in that booster because it locked the shoulder belt to the top of his shoulder, but I never really let him use one after that until he was 6 because that booster was technically illegal for me to use since it was British (was legal for the mom who picked him up to use though because she is a British citizen). He still isn't a particularly good booster child, but does ok to ride in one ( and in the adult belt in a couple of cars) for short trips. If he going somewhere more than 30 min or so away we install a 5 pt for him though. I made the mistake of thinking he would be ok on the way to Disneyland in the Bodyguard a couple of weeks ago because my mom needed the Radian for my cousin. ( word for the wise, Jeep Patriots really suck for car seats) We weren't on the road for 2.5 hrs and I was stopping to buy another Radian. Very expensive reality check. It's ok though since I needed to get a second one before winter anyway.
DD2 ( now 5.5 yrs) , by the time she came along I was smarter than I used to be. At 2 I started booster training her by putting her in a booster and buckling her up in the driveway while we waited for the sibs to get their school stuff and get to the car.If she stayed still, she got a sticker or a happy face. She never actually went anywhere in it until she was 4.5 yrs old. (lol, she wasn't even allowed ffing until she was 3.5 yrs) She was only 35lbs at 3.5, but hit 40 lbs less than a year later, and at 5.5 is now 60lbs
When I got divorced I had to start letting her go occasionally in a booster because I didn't have a car so a lot of people in my family helped me out with transportation. A booster is a lot easier to carry through a store, Dr. office, etc than a MA. Actually, she sits really well in a booster. I hate putting her in one just on principle though.
Neither of my little ones will go into a booster full time for at least another 2-4 years. DS still has about 3-4 inches before he hits the top slot of the Husky, and DD is even shorter than he is. She still is an inch below the top slot of a MA. Which she outgrew by chubby thighs about a month ago. She may hit the weight at about the same time as he hits the height at the rate she is going.
Kimberly