What are mixer taps?
We've all used mixer taps - they're the variety that combines (i.e. mixes) hot and cold water so that it comes out of a single spout at the desired temperature. Mixer taps are the defacto standard these days, because the alternative is to have two separate spouts - one of which spits out freezing cold water and the other which pours scalding hot water.
Separate taps are practically nonexistant in Australia these days, but they're still commonly found in the UK (much to the confusion of Australian tourists).
What are the benefits of single-lever mixer taps?
Single lever mixer taps are taps that use a single paddle or stick that lifts up and down to control the flow of water, and twists side to side to control how hot or cold the water is. Again, everyone's used this kind of tap before, but you may not be completely aware of the benefits.
Single-lever mixer taps are particularly useful in kitchens because they can be controlled with parts of your body other than a gripping hand - meaning that you can turn them on and off even if you have your hands full, if necessary. These taps also make a massive difference to those with mobility impairments or arthritis, because they require far less dexterity and force to turn on and off, and because the tap can be fully turned on by moving the tap a relatively small distance.
What different types of mixer taps are available?
As with most other types of plumbing fittings, there are countless different styles, sizes, finishes and materials available when it comes to mixer taps. When you choose your taps, remember to consider their size and where they'll sit in relation to the wall behind the sink. You'll need to ensure that there's sufficient clearance both for the tap lever, and for your hand to control it. Likewise, if the lever's facing forward, consider how it may get bumped by dishes in the sink.