Young and healthy cats: Once or twice a day is usually enough. They are independent and might be resting or playing on their own.
Senior or sick cats: You might want to check on them more often to make sure they are comfortable and eating properly.
Outdoor cats: If you have an outdoor cat, checking once a day is often enough, but keep an eye on them to make sure they're safe and well.
Cats with anxiety: Some cats might need more attention and reassurance, so you might check on them a little more frequently.