How often do the diamond and diamond discs have to be cleaned with the brass brush, water and a drop of dishwashing product?
Unless there are residual wax on the edge, the Roto-Finish diamonds get dirty. On the other hand, fixed diamonds get much dirty. The ideal is to clean each use or every two to three uses and the diamond discs when they look dirty (pull discs to remove).
Always sharpening before waxing!