One of the most requested services that I perform is blade thinning. Since a knife is basically a wedge (triangular in cross section) it's easy to use and sharpen them to the point that they begin to earn this "wedge" description. This can be caused from improper sharpening, edge damage repair, or simply just from being a thicker knife that's been properly maintained over many years. There comes a point where thinning at just (or above) the edge doesn't work any more and the performance has tanked - this is where I come in.
What I do is I thin the knife back to what it's thickness once was, or even thinner, down into the edge. The knife is instantly transformed into a cutting machine again, it looks better too, and it is now MUCH easier to sharpen into the future.
Here's a very typical example of what I do when thinning a gyuto. I hope that you can see the difference in the blade's thickness from the before & after pictures. Again, this is typical, not in anyway a special job and it's typical of what you can have done to your aging knives if interested.