That’s what we all want our characters to be, right?
Well, yes and no.
We want our primary characters to be well-rounded, the sort of free-standing personality that, if one of them were done in marble instead of words, the reader could walk around it and view it from all sides. And we want our secondary characters to at least stand out from the background in high relief. But when it comes to the great mass of minor characters who populate our fictional worlds – the assorted spear carriers and exposition delivery persons – we don’t necessarily need that at all.
One reason we don’t need it is that readers are trained to expect significant things from characters or other story elements that are described in detail. (The cinematic equivalent to this is the Elevator Operator Rule, which states that if the camera’s eye returns to an unnamed walk-on character three or more times, he or she is going to be important later.) If you take the time to let your reader know that the postal delivery person had dry toast and scrambled egg whites for breakfast, and that she’s three days from retirement to a mobile home park in Florida, your reader is going to assume that he or she needs to remember that postal delivery person because she has a role to play in the story beyond simply slipping the actual plot-important letter into the mail slot of the protagonist’s house.
You can play with this a little, if you’re aware of what you’re doing. Maybe your spear carrier or exposition delivery person is going to have a brief page or so of interesting action before leaving the story for good – the equivalent of a walk-on part with a couple of really good lines in it, the sort of scene that later has casting directors saying, “What about So-and-So for the role? She was really good in that scene in Another Person’s Story, the bit where she tries to deliver the letter and finds the body instead – who’s her agent?” If you’ve got a scene like that, you can bring your spear carrier out into higher relief with a few details like the scrambled egg whites or the mobile home park in Florida. Not a lot of detail, mind you – the light touch is best here.
(And be careful about those characters on the verge of retirement. Readers have been trained on what to expect from them, too . . . and it’s almost never fun for the character. Finding a body on the front porch is probably the nicest of the possibilities for our example above; she’ll be lucky if the envelope she’s trying to deliver isn’t rigged to explode.)