It must seem to you, that it's taking forever to get done with something as simple as the legs... It ain't simple. The folds and wrinkles in the leather leggings have to make sense and since the leg is 360 degrees around, they have to work with the back of the leg as well as the front of the leg. Unlike drawing and painting, this is a 3 dimensional work.
Photographs below show the progression of forming these wrinkles.
Below is a photo of wax and a comb. You'll see a short video explaining both below the photo.