Considering I have only had these flip flops for 3.5 days, so far I am having no problems at all.  They seem to be very well made, the crocheted part is nice and doesn't irritate my feet at all, and they are the perfect thickness of foam to be perfect shock absorbers for my knees.  Time will only tell if they continue to be as nice to me as they have so far, but I think as long as I don't do anything to ruin them myself, normal wear and tear will not be a problem at all.

*Update 5-20-2013*
Almost a month later and these shoes are still pretty good.  I noticed recently that I tend to put more pressure on the inside of my feet when I walk so the foam is starting to get a bit thin up by my big toes, but if it gets to the point where I have to buy another pair of flip flops, these are still top of my list.  Continuing the 5 star rating because they are so comfy and, even though they are wearing down a bit in the front, they are still very much in tact and that is wearing them almost every day and having to walk everywhere.