It's all about the angle
To properly sharpen a blade, you have to keep a consistent angle on the sharpening medium, and you have to use the smoothest surface that is necessary for the desired effect. This results in an edge with the proper geometry and smoothness while removing as little steel as possible. Knives are very durable, but there is only a limited amount of steel you can remove from the edge before they wear out. If properly sharpened and maintained, a good knife can last generations.
Power tools are a last resort
I use ceramic rods and diamond plates, held at just the right angle, to achieve the sharpest and most durable edge possible, while removing a minimum amount of steel. Normally, I won't use a power tool on a blade unless I am repairing it (see the Repairs page for more info). I treat your knives as if they were my own, because I want you to have the sharpest and most useful knives possible. It's a joy to use a properly sharpened knife and it's actually safer because don't have to work nearly so hard to cut something!