i swap it out about once or twice a month....when i go on weekend "fun rides"...monday-friday is my 55+ miles of freeway commutes and city crawl which i do with the 15t....the 13t goes on when i'm just riding local streets out to the twisties for some mountain fun...usually never go speeds past 50 mph....

the sprockets look fine...i use some grease on the cs nut...i could use a new washer because i've bent and unbent it so many times there isn't much to bend anymore....

 

Dude! You change that thing once or twice a month, that's crazy! Do you really feel the torque is that bad with the 15t for farting around in the hills?