Cats kept indoors live much longer than cats that roam outside, but they also need more stimulation to keep their minds sharp. From kittenhood, you should provide your cat with things that keep them mentally fit, such as scratching posts, a variety of toys, and puzzles for play and mealtime. As cats age, continue to spend time playing with them, and keep them occupied with access to a window and vertical spaces for them to climb. You can also work on training your cat throughout their lifetime when it comes to things like walking on a leash, for example.