I have used a diamond stone quite a lot in the past for blades that are really bad. Those take a lot of material off. To much in most instances.
I also have a large two stage natural oil stone that I've used for most of my life. It's from the 1930s and it's really hard. The fine side feels like polished marble. Those are what I've always used.
I've recently picked up one of the Victorinox two stage rods. I can't remember the proper name. You know you're getting old when you've worn out knives. Mostly probably due to over sharpening or sharpening with an abrasive that's too aggressive. I purchased this Victorinox sharpener to see if I can maintain an edge while also prolonging the life of the blade.
I've also got a ChefsChoice EdgeSelect 120 three angle electric diamond hone sharpener. I use that to sharpen my wifes chef knives with. That thing is amazing for those type of knives.
