We ended up getting 2 car seats. One for DH's car and one for mine. We justified it to ourselves by saying we would have a second baby and then both would go in "the family" car and DH would take the smaller run about which currently I drive. So we have the convenience of 2 at the moment and then don't have to buy another one once #2 decides to come along until DS grows out of it (which should be a while).