Apologies for the crummy cellphone camera image, but this was yesterday on the commute home:
I've been using the Kaffenback for just over a couple of years now, so it's averaging about 475 miles a month.
I'm not sure exactly what I've replaced so far, but I know I've replaced one saddle, one gear-brake changer lever (damaged in a minor off), I'm on the third chain/cassette, and aside from the original tyres (which I binned in less than 1000 miles), I'm on the second set of Marthon Supremes. I've also probably replaced the brake blocks half a dozen times, two or three brake cables, and one front changer gear cable, and both wheel rims have been worn out. I just (yesterday morning!) had to swap the front pedals over, because the bearings need replacing. I suspect the Bottom Bracket bearings also need replacing, since there's a slight occasional clicking coming from that part of the bike.
This is mainly used as a commuter, so it's not surprising that things like the gears and brakes are being worn out alarmingly fast.