While cats are very independent, they still enjoy the presence of humans. If you are planning to be away for more than 24 hours, hiring a cat sitter will ensure your cats are safe and cared for and help ease their anxiety while you are gone.
Cats are territorial creatures, and most don't like to be moved, so cat sitting is ideal in most cases. Still, if you are uncomfortable having a pet sitter in your house while you are away, consider cat boarding services instead.