I do 24 hour shifts and these shoes keep my feet happy.  I especially love how easy they are to clean.  In my proffesion they can get pretty gross, so a run under water in the sink and a wipe down and they are as good as new.I think I read you can autoclave them but I have never done that.  I have never had to replace them as a result of them wearing out.  I sometimes donate them as a reason to get a new color.  But I also had one pair for around 10 yrs and only replaced them after I left them in Kenya.  There are a few of these floating around Africa.