There are some basic facts that you should know about sharpening [if you already don’t].
- All “sharpening” involves the removal of at least some material from the blade edge
- It is only the exact edge of the blade that does any cutting~ the rest is merely separating material
- Getting the finest edge is about minimizing the friction at the cutting edge~ the smoother the edge, the finer the cutting action
- The angle of the edge bevel effects the type of cutting action~ slicing/chopping/cutting/shaving/paring
 When we sharpen a blade we work from crude removal to polishing in steps. How many steps you use, and how far into finishing/polishing you go is up to you. Sharpening to a decent cutting edge can end at any point you want and are satisfied with. With files and the coarsest of stones you can actually reshape the entire profile of a blade, change the edge angle to change the utility of the knife, or restore the edge angle on a blunted blade. These all involve serious removal of material, and are futile with higher grit stones… it will just take so long you will lose heart.
Working up to a good cutting edge is done by changing to increasingly higher grits of abrasives that remove less and less material at each level. This is commonly done with a series of graded stones or diamond hones, and finishes with stropping on leather with very high grit [1000-3000+] polishing compounds that leave the edge with a nearly frictionless, mirror-like finish.
 The point of separation or cut on a blade is on what is referred to as the “micro-bevel”. This is the real edge. The area behind this is really just forcing the cut material apart. However, both of these surfaces effect the cutting action. If the main bevel is still rough, the blade will have higher friction pulling through the cut. It will feel less efficient, and your results will be cruder. [Most knives are finished with two bevels… one that provides the transition from body to edge, and the micro-bevel that performs the cutting. The exception is on “convex” ground blades which curve continuously all the way into the cutting edge. We are going to ignore convex blades for right now… if you’ve bought one, your knowledge is probably already past this faq].
 As you refine the blade edge you remove less and less material. This is why maintaining is better than having to restore. What you need to appreciate is that the material does not all get removed. Some of it feathers up on the opposite side from that being sharpened to form a “burr”. [You can see this best with a file or grinding wheel. A fine flange of metal is turned up away from the edge in a curve] When you turn to the opposite side, the burr gets pushed in the other direction. No matter how fine a grit you are working at a burr is produced… it just gets finer and finer. The finest edge involves reducing this burr to its most negligible point.
The second concern in sharpness is that as you refine the edge there will always be roughness on the sides of the bevel back from the edge. This causes friction and drag as the blade moves through material as you cut. The less roughness the better and smoother the cutting action. On damaged/blunted blades you have to repair the main bevel before you can set the micro.
At a magnified level you can always see indications of each of these, both burr and bevel grooving, as well as the “toothing” that will always remain. These all cause friction in the cutting action, no matter how minimal. How much you choose to refine them away is what is up to you.
A final consideration is that finer angles means the blade is thinner for a greater distance back from the edge. Thinner means that it becomes easier to “turn” the blade, which is the deformation and degradation of the edge… bending, toothing, and blunting. These choices are dictated by what your intended use might be for any given blade.
 Most edge bevels range from about 16°[most acute/finest] to 30-35°[most blunt]. The finer the beveling on the blade the easier the cutting motion. At the sharpest angles you start to be limited in just what you can cut without starting to seriously blunt the blade. If you try chopping with a 16° edge it is going to bend to the side under the impact, or possibly even chip. If you try slicing with a 35° bevel you are pushing into and against the material as much as cutting. The blade will deflect away sideways due to the wider bevel in harder things and simply give a less clean cut in softer ones… think cutting into a steak with an axe blade. You want a different angle for campfire chores than you do for cooking or whittling. There is nothing more frustrating than trying to cut carrots or onions, or to get fine curls on a featherstick for a fire, with a wide beveled blade.
Once your blade is sharp, maintaining the sharpness becomes exponentially easier. On a properly sharpened, and properly used knife, the edge can be maintained by a quick stropping on a steel or leather strop charged with a compound. This is also sometimes called “truing”. These work by straightening out any deformation of the edge and removing any burr that is caused by use.
A sharp blade cuts easily, cuts clean, and cuts long.
[top image from KnivesShipFree.com … one of my favorite, drool-worthy sites]