these clunkers are for brief&casual garden/outdoor use only. not all birkenstock clogs are equal. if you want a clog that you can wear for 12+ hours without slipping get the BIRKI PROFI....they last me about 7yrs or more working 60+ hrs/wk. i have seen people survive in "super birkis" (more affordable) but they're not as cush as the PROFI and the heels don't come up as high so your feet get wet easier. do yourself a favor and add a cushioned sport insole (i like the 1/2 length with additional arch support) on top of the original one. again, GET THE BIRKI PROFI. cheers.