A writer e-mailed me to ask, "Is it OK that my book covers only like a month in the entire novel, and that I don't skip too many days?"
This is a great question! I'm amazed by the things you guys think to ask.
In short, yes. Books can cover any kind of time span. Pillars of the Earth by Ken Follet spans several generations. Sarah Dessen's books are often set in the summer. The books in Meg Cabot's Princess Diaries series usually cover a month. I'm trying to think of a book that only covers a day or week but I'm only coming up with movies. Orange County (which is one of my faves, being a writer) all takes place within 24 hours, I'm pretty sure. I have a fantasy about writing a book that takes place within 24 hours, but so far the right story hasn't presented itself.
There really is no ideal of "a book should cover this amount of passing time." You just do what the story needs.