What is it about those that need less? I personally have been sleeping 5-6 hours per night for decades. In my mid-30's I stopped my youthful partying and found I did not need to sleep as much. Now, at 52, more than 6 hours feel like too much and I'm groggy.
Despite knowing that I just don't need a lot in the way of sleep, it seems that every time I make that claim, it's met with incredulity, but having worked a job for 6 years in a different time zone, and with a loose schedule, whenever I just went to bed when I got tired, and woke up when I woke up, I found that the median sleep length was in the 5-5.5 hour range.