I'm a home user and when I bought the machine they were selling X-Grind rings. I didn't get it with my initial purchase, but when I went back to buy one a couple months later, I couldn't. Even though I wouldn't use it that often, I shouldn't be punished for the stupidity of others. Maybe I'm just more detailed, but I don't go more that 4 or 5 sharpenings without vacuuming out the tray, top of the air filter and the machine in general. So now because some dummies didn't clean there stuff properly I'm not allow to use something that was originally available. Is it a "necessity"? No. However, it was one of the selling points of why I purchased one in the first place. I didn't want to have to go to my LHS to have them cross grind new steel when I buy it. That's why I bought my own sharpener. 🤦♂️