You might think its a huge deal, but if poorly chosen, can impact the look and functionality of the whole room

Your faucet and sink tend to be the most used areas of a kitchen, inviting the most amount of attention by family and strangers. It's contrast with other elements of the kitchen counter make it a key design focal point that can tie an entire room together. A new faucet can change the look of a room, making it the easiest way to finish a kitchen Reno or just to refresh an already existing one.
Before choosing your faucet, you should make sure the style matches with the rest of the environment and meets the functionality you need. A good faucet that meets these requirements will add value to your home and your life for years to come.

Sizing your kitchen

This is were the planning comes into play. It's easier to find a faucet that fits in a particular space than to rebuild around a particular faucet. Your faucet will need to have a high enough spout to be able to clean large items but also low enough to avoid excess splashing outside the sink.
Consider how high or low you need your faucet to be. Measure the distance between your backing wall and the sink. You will also need to check the installation area to make sure it has room to fit the height, depth and width of your sink. Measure the distance between the wall and the edge of the sink to see if your faucet can fully extend to cover the distance.

Installation types

Determine whether you want a wall mounted or counter/deck mounted faucet. Counter faucets are exactly what they sound like. Wall mounted faucets and usually seen in more commercial and industrial environments. This could be hotels, restaurant kitchens, factories,...etc. It also can be used as a space saving as the plumbing would not take up any space in the room.

Types of valves

Valves control water flow and temperature inside the faucet. Different valves have different design capabilities and restraints adding to the maintenance they will require over the years. There are many types of faucets but most commonly four main types are used,

Ball valve:
A ball valve can be seen as a single handle at the bottom of the base that controls the flow and temperature of water by rotating or pivoting the handle.

Disk valve:
A disk valve is where the handle moves up and down to control the flow of water and side to side to control the temperature. There are two flat disks inside the faucet that create a seal over the water flow, where moving the handle separates the disks allowing water to pass through. This valve can be replaced without replacing the entire faucet.

Cartridge valve
Cartridges valves are hollow and are usually found in faucets with blade handles because they are only turned 90 degrees. The cartridge rotates to block water inside, where moving up and down allows water to flow and turning the handle left or right controls the temperature. With multiple handles, hot and cold are controlled by each separately. Cartridges can be replaced without replacing the entire faucet.

Compression valve.
Compression valves are usually found in older style faucets. With traditional 360 degree turn screw knob handles, for hot and cold, turning them will loosen the internal washer that holds the water line. These valves are prone to blowing or busting meaning that the whole faucet would have to be replaced.

Number of faucet holes

Depending on your sink style, you're usually going to have pre-punched holes drilled into their deck for plumbing fixtures and can be determined in advance. This can be anywhere from 1 to 4 holes. With the single hole option, this is commonly seen with high arch faucets with pull down sprays.
There is also the option of a single hole faucet with a side spray that would be connected by a little pre-drilled hole in the sink deck. Two handle faucets typically have three holes. One hot and one cold handle control the main spout. A bridge faucet will have 4 holes and two temperature handles beside a center water flow pipe. Hot and cold water travel up their separate pipes and mix in the center bridge. If you need any extension from your faucet you will need to add a side spray because the bridge faucet prevents extension.

Faucet finish

There is a variety of materials to chose from but most commonly used are Stainless Steel, Chrome, Nickel, Bronze and Brass. Some of these can be Polished, Brushed or Matte.
Remember what your budget is and what functionality and utility you're gonna need out of it. Figure out what all the other elements of the room are going to look and match the sink aesthetic accordingly. Just remember that some materials are more delicate than others and need more care and maintenance to clean.

Faucet features

Once all of the above has been considered, you might want to look into adding some tech to your faucet. There are many features your faucet can have like a side sprayer, pullout faucet, water filtering and dispensing or any electronic automation.

Hopefully all this will be enough to guide you when trying to find the right faucet for your kitchen and save you the headaches and costs.