I have a Naniwa 3000/8000 combination stone. When it is freshly lapped it is covered in speckles. I suspect that these speckles are the compound that does most of the cutting. Recently I have been finding that these speckles become loaded with black stuff very quickly and the hone doesn't seem to be working effectively.

So I wanted to ask you all who use Naniwa stones, how often do you lap your stones? After honing how many razors do your Naniwas become loaded up with black stuff?