Toward/Towards

I've been editing my Civil War horror novel today and had to dive for the Chicago Manual of Style to find out if toward or towards is the preferred usage in American English. I use towards, but I'm Canadian. On the other hand, I've lived in the U.S. a long time and I hear a lot of Americans say towards. So basically I had no clue which one was correct.

It turns out toward is the preferred use in the U.S., and towards in the U.K. That meant I had to use Find And Replace to change it in my manuscript.

Which led to an interesting discovery. I use that word way too much. I came across about forty uses in a 383 page book. I would have never noticed if I hadn't had to change it. It's such a common word, a throwaway word almost, not one a writer generally agonizes over. But if you use any word too much the prose starts to sound repetitious.

I managed to replace about a third of them with other constructions, but now I'm wondering--what other landmines are waiting for me as a make another pass through my manuscript?