BSMITH and Andy,
You guys are both on the right track when it comes to understanding what's going on and creating (or following) a regimen. Let's see if we can refine your understanding.
There are two aspects to dulling: Wear and waving/rolling.
Every time a knife gets used a little bit of the edge "wears" away.
This means the edge which touches the food gradually broadens out. Speaking of the edge ... Because it's so fine it tends to bend a little bit, and even though the edge itself is still narrow it acts dull. When the edge is pushed back and forth, it's "waved," and when it's folded over on itself it's "rolled."
There are four parts to sharpening: Profiling, sharpening, polishing, and honing.
Profiling is the first part of a major resharpening. It's something most home knives only need a couple of times a year. A very hard knife, like a good Japanese made blade, would probably only need it once annually -- yo BoardSMITH. Profiling means moving a lit of metal in order to set or reset the bevel angles which were improperly set to begin with, or deformed with wear. On top of normal wear a lot of home sharpeners "feel" the old bevel and sharpen to the feel. Without getting to the whys and wherefores, over time, that makes the edge angle increasingly obtuse.
Profiling is done with very aggressive, coarse stones. Anything coarser than 250# ANSI (American) or 500# JSI (Japanese) is a profiling stone. They move a lot of metal in a hurry. These stones leave a lot of scratch on the bevel, and a very rough edge. If you're sharpening a good knife, it's a good idea to hold off on these stones until you're sure of your technique. You can do a lot of damage with them.
Sharpening is the second part. If the knife isn't too worn the edge can be restored on a medium stone which doesn't remove too much metal. If you've just profiled the knife, the "sharpening" part of the procedure may be no more than the first stage of polishing. Usually though, it involves creating a "fresh edge" by drawing a "wire," aka "burr," then breaking it off clean; i.e., deburring.
The sharpening grits may slightly overlap profiling grits and overlap polishing grits by quite a bit. Roughly 350# to 1200# ANSI, and 600# to 2500# - 4000# JSI (depending on the stone -- waterstones vary). Most home users find that an edge finished towards the high end of the "sharpening" range is plenty of polish. The edge will be fairly smooth but with a tiny bit of bite. Unless you're cutting a lot of sushi you probably don't need more polish. For instance, the most common final stone in the meat cutting industry (and most restaurants as well) is a Norton fine India, whcih is right around 350#
Initial polishing will remove all the micro-serration from the edge, useful when a super clean cut is needed for shaving or raw fish by way of examples; but after that it doesn't do much to actually make a knife sharper. For culinary purposes anything beyond a JSI 8,000# to 12,000# polish is vanity. It might be worth mentiong that as polishing becomes increasingly fine, western style sharpeners tend to strop (often using pastes) while Japanese style polishers continue to use the same back and forth sharpening action on stones.
"Honing," which is straightening out rolls and waves, can be done on a flat stone or a rod hone. On a rod or oval hone it's sometimes called "steeling." Knives with highly asymmetric bevels such as single sided Japanese knives don't do rods. Instead honing is done with a "touch" up on a fairly fine stone. You can do the same thing with a western profile edge as well -- although a flat stone won't work nearly as efficiently as a rod.
So what does all this mean for the home user who does not use stones?
For a typical chef's knife, of "good" quality (like a Wustoff), steel it at least twice a week. Get a gizmo like a "Sharpmaker,"sharpen it every six weeks or so. Send the knife out for a professional sharpening at least once a year.
Alternatively, if you have a three stage Chef's Choice, use the finest stage as your steel, and run your knife through it a couple of times a week. Every couple of weeks, use the second stage. Twice a year use all three stages.
Although it can do an adequate job on fine Japanese knives, I wouldn't use a Chef's Choice for anything really good. This isn't so much out of fear that the machine would do damage (the asian knife Chef's Choice models won't), but part of the joy of a really good knife is maintaining it. In other words, pure hobbyism.
Japanese knives with very asymmetric edge bevels are different and requre different maintenance. My maintenance schedule would be something like: Every other use on a polishing stone. Every week to every other week on the sharpening stones. Every month or so on the basic sharpening stone (~1000# to ~1200#), and twice a year reprofiling. That said, BoardSMITH's regimen seems fine to me too.
Apropos of nothing, I favor a four stone approach: Profiling, basic sharpening, sharpening/polshing, and polishing. If you want more polishing than this can develop I suggest stropping on chromium oxide or diamond paste on some sort of float.
Apropos of a tiny corner of sharpening: Don't believe Norton's grit numbers when it comes to Arkansas stones. Novaculite crystals (they do the job in all Arkansas stones) tend to all run about the same size. What makes Arkansas stones different is the matrix which holds the crystals and the number of crystals in it. Furthermore, Arkansas stone performance on the particular vein and mine from which it came.
BDL