I realize everyone has a different foot type, but those of you that do exercise/run on a regular basis what type of shoes do you have? I've heard that it's wise to replace running shoes every 3-4 months, any truth to that? I'm towards the end of my backgrounds for a law enforcement agency and I've been running a couple of miles every other day in preparation for the academy, doing well so far but considering my current running shoes i also use for the gym and work they're a bit worn out, i plan on getting some dedicated running shoes now, if it means anything i run mainly street, and occasionally on a dirt track, thanks