As kittens, cats always seem full of energy as they jump everywhere and anywhere. However as cats get older, they require extra care that you might never have thought about when they were younger.
For example, mobility will often become a problem with cats so make sure they can still get to their food and water along with their favorite bed and litter box. If a litter box required too much climbing over a high wall, you might need to get a litter box with lower walls or a ramp.
Also consider getting ramps so your cat can still get to his or her favorite couch or windowsill. Just like humans, older cats lose their mobility so you may need to adjust your home accordingly.