Let me start by saying my first daughter wasn't even a year old when my second was born, so would have almost had to double up on everything like if we'd had twins. I really didn't want to have to take that route.
Knowing that now.
My youngest was 4 months old and able to sit in the highchair but yet my oldest was only 15 months old and still using the highchair, not wanted to have to buy another highchair for which we really didn't have the space for, we decided on the Safety 1st On The Go booster seat.
The Safety On The Go booster seat can be used as a booster or highchair, it is made of very durable heavy plastic, it has a removable tray that is dishwasher safe, easy to clean and it made with a little dip so if something get spilled it will stay on the tray and not leak to the floor. It is portable as the back of the seat just folds forward and the tray clips on, there is also a built in handle to carry it, 3 point adjustable safety restraint, built in retractable strap to hold the booster in place on the chair, it is adjustable to two height just by folding the legs under. And lastly a little storage compartment on the back of the back rest.
My daughter is now 3 years old and is still using this chair, and when we got it was previously used, this booster has held up really well without any slips or movement on any chair or surface. We have used it strapped to chairs, and by itself on the floor with the tray attached.
This is great for those who have grown out of the highchair, or those who just don't have room for a large stand alone highchair.
For ages 6 months to 4 yrs.