That question depends on the individual. Just as with automobiles and other precision engineering, it usually costs the most to extract the last little bit of performance out of a mechanical product.

The Chris King hubs, first of all, are works of art in their own right.

They are available in many colors, and in the ISO (disk brake compatible) like the one on this front wheel,

or Classic (rim brake) versions like those on this rear wheel.

The main difference between the two is that the ISO has tabs and threaded holes for the disk brake rotor to be mounted on.

These hubs run smooth as silk, and are easy to rebuild for the average home bicycle mechanic. A total breakdown is said to require a specialized tool, but with regular simple tear downs and re-lubrications, a total, or complete breakdown of the hubs may never be needed, or if so, it will be a few years down the road with just routine maintenance until that time.

For the standard, or routine maintenance, all we use are a couple of Allen wrenches. Chris King sells a special ring drive lube to use in the outer part of the rear shell, but we simply use the same 10W Mobile synthetic motor oil that we use in our automobiles (instructions are available on their website about this). The Chris King team recommends this 10W synthetic oil for colder weather, and says it also works fine in all weather. Saves money too! A teaspoon, or so,  for free taken from our automobile vs about $10 dollars for ordering the specialty ring drive lube. The axle bearings themselves are going to need the regular (synthetic) bicycle bearing grease though.

One thing about running the motor oil in the rear hub is that it makes it nearly silent. Many might like this, but with the standard ring drive lube sold for these hubs, the rear hub sounds like a fishing reel, and we loved that sound, but will do without it for the convenience of not ordering these specialty lubes and using the 10W motor oil we have on hand instead.

The Chris King website has all kinds of videos and manuals available for reference on any kind of upkeep or repair you may want to undertake. Please consult these as they from the people who build them, and the hubs are often updated along with new maintenance requirements that go along with these upgrades, or newer versions. Chris King will usually retrofit any upgrades to your hubs for free minus any shipping charges, which realistically might be substantial since you probably now have spokes and rims attached to them, that will need to be shipped also.

We don't see using a different manufacturer of hubs for our machines, other than Chris King, any time in the near future, as these are built to last and a pleasure to ride on. So, if you can afford the initial and substantial cost of these hubs, we would have to say they are worth the money. We have worn out many other hubs within the same time span that these have been running, and these appear to not even be a small fraction of the way through their lifespan.

There are also heavy duty hub sets (or extreme use), and upgradable parts available for Mountain bikes, downhill machines, or free ride types to even further extend the durability. Stainless steel axles, mounts and shells can be installed to bombproof the hubs.

The most useful upgrade we have seen for mountain bikes is a stainless steel rear shell that the cassette slides over and locks on to, as apposed to the standard road bicycle aluminum. With the Shimano XT, XTR and many other brands, the standard aluminum Chris King rear shell gets gnawed by the smaller separate cogs, on the rear axle, that are not part of the unified section of larger cogs,  mounted on the alloy carrier, which all together make up a mountain bike cassette.

Not all will want or need this stainless steel shell, as even if the aluminum shell gets gnawed it is easily lightly filed to smooth again.

There are really good reviews of all kinds of bicycling components at --> mtbr.com

It's a valuable place to spend some time while deciding which parts are right for you.

Vote below if you would like.

Thanks for the interest,

Hornwaddler