I am going to talk just briefly about author intention, reader comprehension, and theme.
I recently got into a Facebook argument over this picture. (I know, getting into Facebook arguments only leads to bad things. Consider the lesson learned.) The argument involved several authors on both sides of the fence. In my personal opinion, if the curtains were “just blue,” then there would be no reason to call attention to them. Color symbolizes a great deal in literature (and if you don’t believe that everything has meaning, I recommend this book). Blue curtains means something entirely different than red or yellow curtains. And as an author, you should always be aware of the choices you are making, however mundane.
Also, it can be confusing to readers to put details in that don’t end up paying off. Here they are, trusting totally in you, and reminding themselves: “Okay, the curtains are blue. She mentions this several times. I bet this is going to be important later.” And if it’s not important? Your reader will feel some unresolved discontentment, however small.
On the other side of the debate was the idea that, just like in real life, not everything has to have meaning. For example, if we were to walk into my room (ignoring the clothes, craft supplies, knick-knacks and books EVERYWHERE), the fact that my curtains are ill-suited for keeping out light and are patterned with worn leaves and roses doesn’t really mean anything except that I’ve been too lazy, since the day I moved in, to buy new ones.
But does it mean something?
I still contend that, even if the blue doesn’t necessarily reflect on a theme (thought it might)–say of water/rebirth, or of sky/freedom, or of dejection/introspection–it certainly does reflect on the mood and character. That choice (or lack thereof in my personal case) means that the character chose blue curtains. For what reason, we may never know, but the character certainly didn’t choose orange ones. And that says something.
I’m curious where my fellow critique buddies (and other writers) are on this. Are you aware of these details? Are you always mindful of theme? Or does it really not matter, especially in more genre-driven stories?