Something you might want to think about if soap going away too fast bothers you.
Soap is packaged damp. Because of this, as you wash with it, it washes away from the bar faster. The bar dissolves faster.
If you buy several bars at at time, and take them out of their little hermetically sealed wrapper, and put them on the closet shelf, and allow them to dry out, once you do start to bathe with them they last quite a bit longer.
As for the hollow in the dial - when the bar gets so little it is impossible to hold onto, and I get a new bar, I used to throw the sliver away. Now, after using the new bar the first time, while it is still damp, I set the sliver in the hollow. As the bar dries the sliver melds into the bar. I don't throw soap away any more. No waste.