My program didn't have a volunteering requirement, but I had done five years beforehand so I certainly was going to mention it and the professor who wrote my recommendation letter referenced it as well. I think anything helps, but obviously the more time the better.
before they look at your volunteer hours they are gonna look at your prereq GPA. i suggest you worry more about that. then i would worry about your TEAS results and then volunteer hours. 100hrs is usually the minimum for some of the schools i went to. anymore than that, in my opinion, didnt matter.