Your relationship to the person on whom you are spying matters. If that person is your child or your employee, you have a lot more leeway when it comes to monitoring their activities. If you think someone is spying on you illegally, file a report with local law enforcement so they can investigate your case.
Most cats snooze around 16 hours per day. The majority of their sleep time, however, is much shorter than the typical seven hours or so that humans average at. night. Cats tend to sleep lightly, without going into a deep sleep.
Anywhere from 16 to 20 hours a day, typically. A newborn sleeps almost 24/7. Cats do spend at least two-thirds of their lives asleep. Cats are crepuscular, that means they are most active during twilight. So usually while you are asleep, cats spend their time awake, investigating your house.