Chefs Choice Two Stage Electric Knife SharpenerOnly when you buy this thing will you discover that you must 'Break-In' your knives as follows; Stage 1: to 'reangle'(!) the factory edge. With newish knives 15 to 20 pulls are required; with dull knives more than 20 pulls may be required through each of the first two slots followed by 4 fast pulls through each slot. Unlikely but let's say all goes well and it only takes 40 to 50 pulls to Break-In ONE KNIFE. (Note that 'Subsequent resharpenings require fewer passes in Stage 1' (but not Stage 2)); that's encouraging. Now; Stage 2: the knife needs honing, of course. This requires pulling blade through both honing slots 4 to 6 times and then 8 to 12 fast pulls. This is a further 24 to 36 pulls. Finally, 'test for sharpness... if not sharp enough repeat Stages 1 and 2...
Resharpening requires, Stage 1: 8 to 10 (times 2) plus 8 fast (times 2). Stage 2: 4 to 6 (times 2) plus 8 fast (times 2). That's at least a couple of dozen pulls.
In case you're wondering, my knives never became anywhere near 'razor sharp' and some could be seen to have a slightly serrated appearance.
Finally, if you insist on buying this disaster, beware counting the pulls, you may lose the will to live.