I was going to say 200-300.  unfortunately, I 'train' mostly on sidewalks and streets, which, imo, does a job on the cushioning as well as tread.

I found I had have at least two pairs, one for training, one for the 'real trails', else my training shoes were always in need of being switched out before getting into the wilderness/hills (as I want the max support/cushioning I paid for!)

REI Member Since 1979 YouTube.com/philreedshikes