Distance on shoes

OK, I scanned the topics here and didn't see one that looked hopeful.

I've just bought a new pair of runners, and I want to use the equipment tracker.  Now I've watched the how to video and got the shoes all loaded, with special details and all that fun stuff.  What's I'm not sure on is the total mileage I should put on them.  I realize that every shoe is different, and it depends on your weight, running conditions etc...  I'm just wondering if someone can give me a ballpark range.  Something that I can plug in so I have some idea of when they need to be replaced.

Previously, I've always just worn shoes until they fell apart, or were actually hurting my feet.  However, since I've begun training my run volume is up quite a bit, and using a pair of 'worn out' shoes might not be the best approach.

Thanks in advance for the help!