Here is a detailed article written by a Vet about why one should try and keep cats as inside pets.
"Are you thinking about allowing your cat to go outside without restriction? To make the right decision, you need to know the facts.
The average lifespan of an indoor cat is 15-18 years. For a cat allowed outdoors, the average life is only 2-5 years. There are many dangers that can harm or kill an outdoor cat. (However, there are safe alternatives to simply opening the door; see our article on Outdoor Safety for more info.)
If your cat roams outside, or you're considering allowing it, please read this entire list. Then be honest with yourself, and answer this one question truthfully: can you absolutely, 100% prevent every one of these things from happening to your cat? "
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