Hole count in the sink or countertop
A kitchen sink or a countertop is drilled for a particular arrangement: one hole for a single body faucet, three for a set with separate handles and a spout, and sometimes an extra for a soap dispenser or a filtered water tap.
A single hole faucet will not fill a three hole opening on its own, and a three hole set cannot go into one. The usual bridge is a deck plate, an escutcheon that covers the extra holes and lets a single body faucet sit in the middle. Whether one is included is stated on the product. Establishing the hole count before anything else removes most of the range in one step.
Pull down and pull out faucets
A pull down faucet has a spray head that comes down out of a tall spout; a pull out has one that comes forward out of a lower one. Both do the same job of reaching into the corners of a sink, and which suits better depends on the sink, not the faucet.
A tall pull down works over a deep single bowl and gives room to fill a stockpot. A pull out suits a shallower sink or one under a window, where a tall spout would foul the sash. A fixed spout keeps the cleanest line and is the quietest of the three in a kitchen where the sink is on show, which is why it is chosen for islands and for kitchens designed around plain surfaces.
Touchless and touch faucets
Some of these open on a sensor and some on a tap of the wrist against the body of the faucet. Both solve the same problem: turning water on with hands that are covered in something.
The practical difference is what they need. Both require power at the sink, usually a battery pack or a transformer in the cabinet below, which is a small thing to arrange during a kitchen build and a slightly larger one afterwards. How each behaves without power differs between models and is published with them, so the product page is where that answer sits.
Pot fillers
A pot filler is not a sink faucet. It mounts on the wall behind the range and folds away against it, and it exists to fill a pot where the pot already is, rather than carrying a full one across the kitchen.
It needs a cold water supply brought to a point on the wall behind the range, which is a decision made when the kitchen is being built, not afterwards. There is no drain under it, which is the thing to understand before installing one: it fills, it does not empty.
Faucet finishes
Chrome, brushed nickel, matte black and brushed gold cover most of the range. Chrome and nickel are the ones that agree with the widest range of kitchens; black and gold are decisions the rest of the room answers to.
The faucet is usually seen next to the sink, the handles of the cabinetry and the appliances at once, so it is the piece that reveals a near miss fastest. As with shower fittings, finish names are not standardised between makers, which the shower systems page covers in more detail.
Choosing sink, countertop and faucet
Where a countertop is being cut, the hole count and position are being decided at the same time, which is the moment the faucet choice is genuinely open. A stone countertop is drilled once.
The stone slab range covers those surfaces, and the kitchen sinks page covers the other half of the decision.