We applaud the efforts of customers who take to the stones and do their own sharpening; it's a great way to get to know your knife and potentially save some money. Wait, "potentially?" Unfortunately improper sharpening, especially many sessions of it, can lead to a hefty bill when it is finally time to visit the professionals. If one does not remove a proportionate amount of steel from the secondary edge, but only recreates the primary edge, the edge angle gets wider and wider resulting in diminished cutting performance.
Recently a customer named Vic brought in two Kikuichi knives (which hold up pretty well) for sharpening. He had bought the knives from us during one of our "Complimentary Lifetime Sharpening" promotions, and therefore can bring them in ANYTIME for free sharpening. Because he uses his knives in a professional kitchen and they require more frequent sharpening, he decided to work the stones himself rather than trek over to our shop every few weeks. He owns a variety of stones and expressed confidence in his sharpening ability, but said lately that sharpening was getting more difficult.
Turns out Vic had only been grinding only on the primary edges of these knives, and had carved his way up to pretty thick territory without removing steel from the secondary. Knives in this condition require a lot of additional work (and time) to restore to peak performance. In a sharpening business time is money. So instead of a $0 bill, we had to charge Vic $50 + $40 to repair (i.e. re-profile) the two blades before sharpening them. Tough hit to take for Vic, but we also gave him a lesson on what he was doing wrong, his knives were good as new and he still gets free sharpening.
Takeaways: Properly sharpened knives require less frequent sharpening and cut better, meaning better performance and longer lifespan.
Vic's knives, good as new: