I manually save ALL the time now, using "save as", because the auto saves in my daughters game overwrote my saved games, and the only one left was when I started the game. I have noticed that when I do "save as", it also overwrites one of the autosaves, as the next time I save, they both have the same time stamps. I save when the last sim in the household is going to bed, and usually again when they've gone to school and work, and before they travel, when they get promoted, when they level up....pretty much all the time