Cats are known to sleep a lot during the day, and this is considered completely normal. Here are some main reasons why your cat sleeps so much:

1. Need for sleep:
Cats are natural predators, and they need many hours of sleep to maintain energy for hunting. Even if your cat does not go hunting, it still retains these instincts.
2. Lifestyle:
Cats are largely nocturnal, meaning they are more active at night. Therefore, they sleep for most of the day in order to be more alert at night.
3. Age:
Young and old cats tend to sleep more than middle-aged cats. Puppies sleep a lot to grow, while older cats may be less energetic.

4. Health:
If your cat is sleeping more than usual or seems very tired, this may indicate a health problem. If you're worried, it's worth checking with a vet.
5. Comfortable environment:
Cats like comfortable and safe environments, and if your cat feels comfortable and safe in his environment, he may sleep more.
6. Boredom:
Cats can sleep a lot if they are not disturbed. If they don't have toys or stimulation, they may sleep to pass the time.

7. Nutrition:
An unbalanced diet or a lack of quality food can affect a cat's energy levels. If your cat is not getting all the vitamins and minerals it needs, it may feel more tired and often lie down.
8. Mood:
Cats, like humans, can feel sad or anxious. If your cat experiences a change in his mood or if there are significant changes in his environment (such as moving house, the arrival of a new animal or changes in the family), he may sleep more to cope with his emotions.
9. Hormones:
Hormonal changes can affect the energy levels of cats. For example, if a cat undergoes medical treatment or suffers from certain diseases, this can cause changes in its sleeping habits.

11. Extreme heat or cold:
Cats are used to maintaining a comfortable temperature for them. If the room is too hot or too cold, they may sleep a lot to maintain their body heat or avoid the summer.
12. Social relationships:
Cats are social animals, and if your cat feels alone or disconnected, he may sleep more. Play with your cat and spend time with him to improve the bond between you.
13. Personal character:
Every cat is unique, and some cats are just lazier than others. Personality can affect their energy levels, and some cats just like to sleep.
If you feel that your cat is sleeping more than usual or has a significant change in behavior, do not hesitate to contact the vet. They will be able to provide you with more information and help determine if treatment is needed.