Taps (faucets) drip. It's a fact of life. They rely for their operation on a piece of rubber being screwed down over the end of a pipe. Sooner or later the rubber is going to go hard, and it will no longer seal. Then water starts pushing through, and the tap starts dripping. Leave it too long and the water will erode the tap seat, so you'll either have to re-seat it or replace the tap. Tedious in either case.
But, dear friends, it need not be so. There are now a large number of different designs of taps which use an alternative technology: ceramic discs.
How They Work
Instead of blocking the pipe by thumping a piece of rubber down over the end of it, ceramic disc taps have a close fitting piece of ceramic with a hole through it (usually in at the bottom and out at the side, for simplicity). To turn the tap on, the disc is rotated until the hole in the side matches a hole in the tap body. Water flows. Rotate the other way and the port is blocked - flow stops. Just like a gate valve, only with less winding. Simple.
Why Is it So Good?
There are advantages to this approach. The disc lasts many times longer than traditional tap washers - ceramics are very hard and resist water erosion well. Tap bodies are made of metals which complement this, so that when erosion does occur, it's the disc that goes not the tap itself.
Also, it only requires one quarter of a turn from fully off to fully on. This is particularly good for people with restricted movement in their wrists. Added to this, because the seal is not dependent on a washer being forced over the end of a pipe, the operation of the tap is very light - you can almost always work them with your little finger.
The longevity and ease of operation mean that most good quality sink mixer taps have been made this way for some time, but ceramic disc basin taps are less common - yet equally good. The more use a tap is likely to get, the more attractive the idea of using this kind of tap. This is especially true in hard water areas, which are murder on traditional taps.
Are There any Drawbacks?
Surprisingly few. The discs do wear out eventually but manufacturers seem to have standardised so most good plumbers' merchants carry stock of the right ones. Basin taps are sometimes handed and sometimes not, so it can take you a moment to work out which way to turn in order to get water. But the only real downside is that if you twist the handle more vigorously than you intended, you can get a full-on jet of water, leading to an embarrassing case of wet trouser syndrome.
Now, if anybody comes up with a ceramic disc ballcock1, place your order immediately.