It's a nice idea and I wish it would have worked better for me. Unfortunately, since the shape didn't quite fit my shoe perfectly it caused little parts of the insole to crinkle up over time, creating sharp hard lumps in my footbed that did not feel good to walk on.  By the end of the month I had to discard them because they were too uncomfortable to walk on any more, and they could not be simply smoothed out or cut to size like a normal insole (at least I don't have the tools for that).<br /><br />Overall, I think these are a great idea, but in practice they should either be smaller than the size of your shoe so that the edges dont get pushed up causing sharp spots in the footbed, or you need to have to tools to precisely cut these to the shape of your shoe interior which I think would be difficult to do, but doable with enough dedication.  I wanted to like these and I could certainly use the shoe freshening of this idea, but they just didn't work for me.