I have two cats and I let them be in my house for the whole day, while I am at the university. I don’t see a problem in letting them free in the house. It is actually great to teach them that it is not correct to be on the table or to pee where they shouldn’t. I love them so much and I ordered for them a special furniture so they are very happy to play with them, to scratch them or to sleep on them. You may see modern cat furniture reviews here. it was this link that inspired me to buy it.