I've been using the Davis Leatherworks simple notebook cover for a little over a month now. Per usual I've put it through its paces and found it to put up with my abuses very well.
First off in the hot summer I was walking a lot on the weekends. On days when I didn't want to bring my bag with me it went in my right hip pocket. Since it was hot and I was walking... It occasionally got sweaty. Add to the sweat that I was constantly holding it in my left hand as I sketched the color of the leather has darkened dramatically. There are scuff marks from my pen rubbing under the elastic.
The leather itself is slightly softer than when I got it and its worn ever so slightly to the shape of my hip pocket. Since I don't keep it there often I'm sure that if I did it would be perfectly shaped.