To exactly Richards initial point, MOST people are able to buy knives. VERY few are qualified to go any where near a sharpener let alone re-profile a blade. They certainly have the right to attempt it but that will very quickly translate to the right to own a damaged knife.
I know many intelligent capable folks who have the means to buy nice knives and they promptly ruined them by trying to sharpen them.
It is with the advent of guided systems that the neophite (and his knives) were saved.
For most..... the best advice is Leave it alone.
I think some forget just how difficult it is to do well what they now look at as second nature.
I don't really agree with that. While there is a great amount of skill and experience needed to make some edges at some times, at other times all that's really needed is a lot of care and patience. Just because a person can sharpen a knife really well does not mean they have some kind of raw talent that makes their skills incomparable with the rest of society--though their results often are. To put it simply, sharpening/reprofiling is really not that hard, it just takes critical thinking, patience and practice. Critical thinking accounts for knowing what is being done to the edge, and usually only really requires a person put on their thinking cap--things such as a burr seem academic to some, but to the person thinking critically about what they are doing, they should be obvious. I even knew what the burr was and what it told me when I was a child and never even heard of the burr or knew what to call it, it was just evident what was being done to the blade and how that effected the edge I was trying to form. The patience side of things comes in being able to apply a consistent technique, and not switch from one thing or another trying to make haste, even if progress is very slow and/or if the results don't come out like you'd like the first time--sometimes patience seems like the wrong word, it's almost more like having faith in the conclusions you came to with your thinking despite the fact that progress might be too slow to affirm them quickly. Then of course the real trick is to not practice sharpening, but to practice both the critical thinking and the patience; becoming better at the sharpening itself will come with repetition and experience. This is really true with a lot of skills that require a high level of detail and craftsmanship, so sharpening isn't any different.
I've reprofiled a lot of factory edges just to see how thinning the edge would help--a lot of it is the simple idea of, "Well, this knife steel is S30V, and 40 degrees inclusive is probably much more than it needs to remain as stout as I need it, so I'm going to just go ahead and try 30 degrees." Sometimes I've tried it on knives where the steel was just not going to play along, and then had to thicken the edge out again and that kind of sucks, but overall I don't see a reason why a person shouldn't play with it. As long as they want to invest the time in sharpening it, what's wrong with having a little trial and error?
Personally I've started to shy away from the "thinner is better" concept, because I've found the only place it's really any better to me is when I'm doing something like whittling hairs. On the other hand, if I get clumsy and run my edge into something hard, having one of these more obtuse angles that the factories like to use really helps in edge retention. Personally I think a lot of people asserting, "Well, factories just want the edges to be able to take a lot of abuse for people that don't know how to use a knife," are really looking at it in their own perspective. How about guys like me that aren't the most skilled in the world that might accidentally run their blade into something hard and would rather it be quick to grind out than very long, and just to salvage an edge geometry that for me doesn't really increase performance that much. It's just not really worth it to reprofile sometimes, and for me at least I sometimes find those factory bevels to be better because they're a lot more difficult to mess up and work just as well for the actual practical applications I need them for.
That's not to say that I don't think every factory edge could use a little TLC regardless of edge geometry. Edge finish and coarseness? Well, I don't want to get into that little argument--I don't know enough about the subject. I'm sure I could reiterate all the stuff about "microserrations" everyone has heard, but I think it just boils down to personal preference when it comes to how fine the edge should be polished, and I think the difference in edge retention and wear resistance for each are a little misunderstood. For example, if I take one of my highly polished knives that can whittle hair and I start cutting up cardboard, wood, and whatever tough-but-not-insane material I can get my hands on, I will probably find that I've put quite a few dents and dings into the apex of the edge because it was honed so fine, but when you actually think about how keen the edge is even at that ding it doesn't really matter, it's just not going to be as smooth as a cut. On the contrary, with a toothy edge, those types of dings and dents aren't encountered as often. I don't really have any comments on either in terms of wear resistance and how long the edge keeps coming, but at a certain point that becomes irrelevant to me anyway since I usually touch my edges up far before they have a noticeable decrease in performance.
Anyway, what was I saying again? Oh, yeah, I still think factory edges could use a little extra care. They're usually a bit uneven, the bevel faces are usually pretty convex, etc. I usually like to even these types of things up, even though I'm not thinning or thickening the overall geometry. This can really account for a lot of metal removal though so it is akin to reprofiling, and is probably one of the few things that an unskilled, novice sharpener probably couldn't benefit from because their bevels might come out as uneven and convex as the factory's, but on the other hand I think most users are able to judge whether or not they'd do a better job.
