Right now I have three novels published under my name and have ghost written a number of non-fiction books. I'll have another novel finished pretty quickly and have 4 others partially written, in addition to working on a few other ghost writing projects.
One thing I heard from an agent once was that writers should find a genre and stick to it. However, I think that is analog advice in a digital world.
The main reason for my belief is that it is the publishers who want a writer to be defined in one genre, not necessarily the fans.
I pulled one book from an agent because they wanted me to squeeze it into a pre-defined formula which I really didn't want to do. Instead, I wrote it the way I wanted it and I've sold some copies and gotten good reviews so far. Sure, it isn't on the bestseller lists but I like it and am proud of it.
In addition to the non-fiction, I've written No' Chance, the first book in a series that has been called horror as well as a supernatural thriller. The next book in the series, Second Chance, is in the same vein.
Junebug and the Body is also the first in a series but this one is a humorous mystery. It's set in the early 70s so it has an innocent quality and I have been told that it is both nostalgic and laugh out loud funny in places.
The third novel I've published is The Bottle Tree and the closest I can come to pigeonholing it into a category is literary fiction. It has some humor but is more of a serious book with racial conflicts throughout. The book is set in the early years of the 20th century in a turpentine camp located in the Kisatchie National Forest region of Central Louisiana. I'm proud to say that the camp was real and my grandfather and his family lived there when he was a boy.
So why do I write in more than one genre? Because the story that wants me to tell it doesn't cooperate a lot of times. I've told people before, and I hope that they did't think I was BSing them, that I don't write the books so much as the books write themselves. I do try and write every day and sometimes it is a struggle just putting together two or three coherent paragraphs. However, at other times the characters take over and I just let them go. On those days I can knock out 10 to 15 pages with no problem. As the book approaches the end sometimes the last 30 pages will be written in one marathon session not by choice but because the book took over and I'm just providing the fingers for the typing.
I write in more than on genre because I have more than one type of story to tell. I hope you like them all but they are very different.