To be honest, I don't know how far I am walking. Generally how it works out is that I walk for 75% of my work day, mostly on waxed floors. I also walk for exercise, but nowhere near as often as I used to. The primary problem is that the soles of my shoes split near the front, near the point where my toes bend. Then the material over top rips open, or tears away from the sole. I scuff the toes on my shoes because I bump them into racks of computer equipment. I also wear soles down flat in 6 - 8 months. With lesser brands, I used to wear holes in the soles.
Yes, I do tie 'em tight, because I can't afford to trip and fall over while carrying 70 lbs worth of equipment that may cost as much as my car.
Oh, I weigh 190 on average.