Adopting a cat can be fun and rewarding, but there are also lots of challenges associated with pet ownership. There are a few things you should think about before adopting a cat, as explained in more detail below. ​ Look At Your Finances Cats aren't the most expensive pet you can adopt, but they can cost a substantial amount of money. Make a list of everything your pet will need, and estimate how much it will cost weekly, monthly and annually.