I believe most writers are loathe to leave their beloved characters when they finish a book. Even bad ones can be used again if you don't kill them off. Since I write mostly series, I am able to hang on to the main creations for a long time though they may fade into the background somewhat. My former editor always chastised me for wanting to bring too many old characters back to life and sometimes made me take them out despite my argument that my readers wanted to know what the former characters were doing now. Yes, like real people they continue their imaginary lives, have children, take new jobs, retire, have grandchildren.
I have several single title books that I simply call my Chapelle novels as they all take place in that imaginary town. Trashy Affair deals with a devoted environmentalist who falls for wounded warrior, Merlin Tauzin, who owns with a big ass truck. The funnier episodes were based on my own garbage collection problems. It's one of my personal favorites, but Merlin and Jane were left behind when the book ended. Still, people kept asking about him. I wrote Ashy Affair next, which takes place in the same town, but again I put aside the hunky fireman at the end of the story. Then, along came Putty in her Hands, and I was able to update fans about both the Merlin and the fireman since they all live in the same small town and would know each other. As Julia attempts to save an old hotel from demolition, she goes before the Parish Council, and we learn Merlin now serves as a councilman who decides to help. Jane, always the conservationist, is on her side too, and so is another escapee from another single title, A Taste of Bayou Water, Jonathan Hartz, billionaire, and his Cajun wife, Celine. At one point, the fireman, now the chief, saves the hotel from burning down.
Sometimes, my single title characters even intrude in my series titles. Recently, Jon Hartz, has employed Trinity Billodeaux as coder in his company and acts as his mentor. That book, Dream for a Sinner, one of the Sinners series, is in line edits right now. But in the same title, a retired bull rider, Bodey Landrum, makes a break from The Roses series and shows up at a charity rodeo given by the Billodeauxs along with three other Roses characters. Well, why not? Wouldn't Bodey take off from his famous bull riding school to help out in a good cause? And he'd absolutely take the geeky Trinity out to a honky-tonk and help him out in a bar room brawl. No pub date on this one yet, but probably winter sometime.
Often, people ask me what became of secondary series characters who aren't really suited for a book of their own. A friend recently wondered about the scheming Ilsa and the outrageous Prince Dobbs. I was happy to tell her I gave them a paragraph in the epilogue of The Heart of a Sinner. While not there in person, others gossip about them. Yes, Ilsa is still trying to get Prince to marry her.
If there are any characters you are curious about, let me know. I assure you they are all living full and interesting lives in my imagination. Who knows when they will show up again in my writing?