There are definitely people who, like you, can get by on less than 7 hours a night, but less than 7 is not a great plan for most people. I like people to know, however, that there's pretty solid research indicating that less than 6 hours significantly raises the risk of chronic illness later in life — and one may think all is well until the effects add up over years. (An aside: seasonal variation is normal, too — most of us sleep less in summer, thanks to longer days and warmer nights.)