This is a tricky question. It largely depends on the age of the person, their living conditions, health conditions and a lot more factors that cannot all be taken into account in this article.
However I am glad to share what is recommended by the National Sleep Foundation
For an adult, the average sleep requirement is 7 to 9 hours.
As you already know, we sleep in 90 mins cycles and a typical healthy sleep routine at night should consist of 5 to 6 cycles.
What is more important to note is that we should be asleep between 11 pm and 3 am to get the maximum benefit for our body. Our body is such an advanced piece of machinery that it is programmed to heal certain parts at certain times of the night. If we are not asleep at that time, we miss the health benefits aspects of our sleep and would only get the rest aspect of sleep.
I would recommend that you get to sleep between 9:00 and 10:30 pm and wake up between 4:30 and 6 am to get the full benefits of this wonderful process that has been designed and perfected over a period of nearly 3 million years.
Do you want to know how many hours of sleep the ultra successful people get?