I posed this question to one of the many lists I belong to: how many books should be in a series? How many is too many? How many is not enough?
Of course, my answer is, "As many as they will let me publish!" But it does beg the question. I've read series where I just got a little tired of it all, even when I loved it at first. One simply has to be certain that it doesn't go stale.
In my Medieval Noir series, I attempted to strike a balance in the formula between noir and series. In your traditional noir, the protagonist doesn't change. He's still the same drunken bastard in the first book as he is in the last. But that doesn't wash today. The characters need to change. There must be story arcs. And I think Readers appreciate that. After all, I'm still a Reader and I appreciate it .
I came across these quotes from the latest NY Times Book Review for crime stories, written by Marilyn Stasio. Marliyn writes: "To say that series mysteries are predictable isn't a nasty crack. It's just a way of acknowledging that some stories deliver their satisfactions through familiarity rather than novelty..." Which is the reason people simply LOVE a series. We like sitting down to meet up again with the people we've come to love, seeing how they'll thwart the bad guy this time. And I think we do like our heroes to grow and change--at least a little--and maybe quit fooling around and marry the girl already. "In fact," Marilyn goes on, "watching a hero develop over time is one of the pleasures of sticking with a good series."
Well, Marilyn, I couldn't have said it better myself. Thank you for saying it.