You're the Author; You Should Know

I get really bothered when I read something like "They traveled for 6 or 7 days" or "He was a man between 34 and 37" or "Her sweater was pink or purple." There is no excuse for phrases like this. How can you be so vague? You're the author; you should know.

This goes right along with being concrete and creating definite worlds. If you are telling the story, you should know every relevant fact involved. If you don't know some fact, then either you haven't put in enough effort or it is a piece of information that isn't important and should be left out. And of course, if you do know a concrete fact, you should be specific and avoid vagueness in your writing.

I will admit that there are exceptions to this. If a character is speaking or is narrating a story, vagueness is allowed. A character may not know exactly how old somebody is, may not remember how long they traveled, may have trouble recalling a color (though that may still be better left out if it isn't relevant). I will say, though, that even if the character doesn't know something exactly, you still need to. You're the author you should know everything.