Try it in a few different situations, and once you know what it does, see if you use it.

I don't use a green filter too often, except pretty much in the way Ralph does.

Filters I use most often for B&W outdoors would be medium yellow and orange, and I tend to shoot old-style films like Tri-X, Classic 400, and Efke 100. Occasionally I'll use a light yellow filter or red, but not often.