The problem with letting your cats outside to roam free is that they can come into contact with other animals who have not been immunized. Your cat could contract stuff like FeLV (Feline Leukemia) then bring it back to your house and give it to your other animals.
Pictures of my other cats:
These are my older sister's, but they are staying at our house right now.
They are Blue Point Orientals and are named after the twins in the Nickelodeon cartoon, The Rugrats.
This is my mom's Blue Point Oriental, Lucy, and she is Phil and Lil's 1/2 sister.
Here is my other cat, Leonidas, we call him Leo. He is a Smoked Egyptian Mau.
These are our other 2 Cornish Rexes.
This is my dad's cat, Gidget, she adopted us
We have one more Cornish Rex, his name is Ty. He is a long term foster. We rescued him from a backyard breeder. We picked up 6 Rexes from the lady (Oliver and Anubis were part of that 6), one had an ear infection and ear mites so bad his head is permanently tilted to one side. He was adopted out to a family that had no clue how to treat a Rex. They were giving him baths with medicated shampoo every week. When they returned him to our rescue they said he was very aggressive and was peeing outside the litter box. I can believe the peeing part since he was so stressed, but not the aggressive part. When we got him back he had no hair, was as red as a cherry and very skittish. Now, he has calmed down, loves attention and is as sweet as you would expect a Rex to be. We have seen no aggressiveness at all, actually he is the least aggressive cat in the house.