Human feet were made to wear Birkenstocks!  Okay, I'm pretty sure it's the other way 'round, but you get what I'm saying.  I wear mine almost constantly, even indoors in the winter with (gasp!) socks to keep my toes warm.  These are the most comfortable footwear I own.  Even better than my Asics Gel-Kayano that I wear all day at work.  These are your FEET, we're talking about.  You need to take good care of them.  Don't expect your $18.00 Shoe Carnival sandals to give you the same level of comfort, support, or durability.  When it comes to taking care of your feet, you get what you pay for.  I've worn Birkenstock footwear for almost 20 years and, God willing, will continue to wear Birks for another 20 years or more.