Leaking taps and mixers
Leaking taps are generally caused by the jumper being worn. But often it is never that simple, and may involve other issues.
If not attended to, over time the brass seat that houses the jumper can develop a cut in it. It will have to be resurfaced or, in the worst case scenario, replaced.
The spindle that closes the jumper down has an o-ring that can also leak up to the handle. The minerals and corrosion from this leak can cause the handle to seize up, not allowing the tap to open and close properly.
Mixers, like most modern appliances are usually made as disposable items. The main component of the mixer is the cartridge. Most common brands of cartridge can be replaced easily.
If you have a sink mixer leaking around the swivel spout, a full repair kit may be available if it is a high quality brand (for example Grohe, Starion)
More common brands (for example Ram, Madison, Greens) are generally worn out and replacement is the best option.
Do yourself a favour and always replace with a brand that has 10 – 15 years warranty and 1000 kpa maximum working pressure.