Its alot of trial an error. I work on a pattern, sometimes for days unit I get it the way I want. Then I make the first version of the holster, sometimes one version is all it takes, but more often then not it takes several versions until I get a holster I'm happy with that looks as good as it functions. But the hardest eliment to design is the repeatability. You must take into consideration all elements that can change from one holster to the next and engineer them into the design. Each subsequent holster will have slight differences, but hopefully for the better. I am allways looking for ways to improve my product, I think when you stop trying to improve its time to move on to something else.