Many of the imaginary characters in my Steve Martinez novels bear the names of people I knew in high school. Instead of riffling through phone books looking for likely names, I just pull down my 1958 Evanston Township High School yearbook and find my characters in the class listings.
Of course the real people have nothing in common with the fictional characters, just the names.
For me this method of naming is not only convenient but also an aide-memoire—it helps forestall those vexing moments of trying to remember who was called what.
There are other good reasons, and you'll find them in this droll Op-Ed piece from today's New York Times.