I've always written more than one genre. I like the freedom it gives me to explore different aspects of my creativity. I write non-fiction and historical romances and paranormal romances (lol I always have to have romance in my stories :D ). And just last night I finished a proposal for a zombie story! Not something I'd ever thought I'd write but it's been so much fun :) I guess it's technically still a paranormal romance but it was fun spending time with a monster I don't usually hang out with much :)
I suppose since all my stories are technically romances, the genre doesn't change much. Just the sub-genre. The romance is always the main plot - the only thing that changes are the settings and side stories. Still, I like being able to delve into the past or play in a present that has a few extras :)
Do you write more than one genre? Why or why not?