I track wordcounts if I have a particular number goal I have to reach. Otherwise it's more or less just an interest factor. Generally novels are between 70 and 100k, and I imagine whether or not a publisher picks it up will have something to do with length, but it's not going to be the only thing they consider. The story is more important than the length, so it's not something to aim for so much as something to keep in mind as you go, when considering how much of the story is yet to come and so forth.