Audrey, mine are in/out cats, but we don't live on a busy road (just a quiet cul-d-sac), and I think they would DIE if they had to stay inside all the time, especially since we have four dogs that are going in and out constantly.

If I were an "inside only" cat person, I don't think I would ever let them experience the great outdoors, especially knowing how Mim and Butter love to be outside.

Just my two cents worth. Good luck!