The slipper doesn't stay firm and form fitting for long. It's been just over 30 days since I purchased these slippers and they already feel like the ones I discarded (after a year) and replaced, with these. Gone are the initially plush insole; and the comfortably snug fit. The cushioning is now matted down and the the structure of the slippers has expanded, such that I now have to exert conscious effort to keep them from involuntarily sliding off my feet. Or, I have to wear socks. And again, these are precisely the issues I had with year old, well worn pair of slippers these were meant to replace. On average, I wear these slippers less than an hour per day. It doesn't seem feasible that they should exhibit this much wear, so quickly.