About 7-8 hrs/day. Usually weekends tend to sleep longer.

Some days I sleep for just 2 hours, others it can be as much as 10. It is your choice, so don't worry too much about it!!

I sleep 8 hours a day. Your body needs time to recharge itself. Younger people need to sleep longer than older people.

Wasting? Forget it. People sleep different amounts. My workmate always believed that people need more sleep in winter, when days are shorter. I wake when I wake, without alarm. For most of my life, I slept 4 hours a night. As I have got older, I now sleep about 6-7 hours some days. Studies will tell you that too little sleep affects your memory, especially in children. I suspect that "too little" needs to be defined for each person differently.

5 or 6 hours in a day