Actually, to the degree the Reddit leak is to be believed (sounds legit, but leaked info about a game mode they're still in the process of developing means take it all with a grain of salt,) there is going to be a sleeping bag item that will save your game but not give you regular "sleep" benefits.
Anyway, we've got three Survival Mode topics. I'm going to close this one, as there's already a thread specifically talking about the sleep/save mechanics (http://www.gamesas.com/topic/1593342-should-survival-mode-only-allow-saving-when-you-sleep-part2/) and another thread with a more general overview of the mode (http://www.gamesas.com/topic/1593274-survival-mode-full-overview-confirmed-by-bethesda/.)
Please use one of those existing topics.