We have a cat. We love her. So much that we cut a hole in our laundry room door for her. Ok, maybe that was more for us so we can keep the door closed most of the time (especially when we have guests) and our cat (Belle) can go in and out to use her litter pan as she pleases.
We got the pet door kit at Home Depot, which came with a template to cut a hole in the door and very easy installation instructions. Nobody even notices that we have the little door there until we point it out.
It took Belle a little while to get used to it, but she eventually got the hang of it and we actually caught her on video using the door when we first installed it.
WARNING: This might be the cutest thing you’ve ever seen (we think so anyway)!