I agree with the OP, I'm forever trying to find ways to make my stuff look like it's been used, rather than straight out of the box. I do most of it with shaders for dirt on skin, Vue materials are good for decaying metals and stuff and transmaps for rips, dents are a little bit harder but not too bad if you use the morph tool sparingly inside Poser.
Rebekah, can I take it then that you will be selling here soon from your comment?
How soon?

Injustice will be avenged.
Cofiwch Dryweryn.