My issue is that I have so many knives (about 200 at last count) plus kitchen knives, that it's hard to develop a feel for such a wide range of thicknesses and lengths. Plus different knives for different tasks need different grinds. I find that the Lansky takes away some of the guesswork. I can sharpen my Fairbain Applegate, Gerber LMF, and Kershaw Needs Work with my eyes closed using a cinder block, because those are the ones I carry most often. For others though, the guides help.

That said, the built in sharpener on the LMF is remarkably good for a quick buff up in the field. Most pocket sharpeners are junk, and ones integrated into the sheath are even worse; but Gerber got it right with the LMF.