R is at 100th percentile for height and if she keeps at this rate, she'll grow out of her infant car seat in the next two months, at 6 months!

we have two bases (one for each of our cars) for the infant seat for ease of use, but do we get two convertible car seats so we don't have to reinstall each time we use a different car? that seems like a big investment. sorry if that's a dumb question.