Safe and Simple Light Switch Swap:

This instructable is for anyone who needs to swap out an old light switch for a new one. For the most part, swapping out a light switch is going to be an easy task. This instructable will take those who aren't as comfortable with home electronics through a safe and simple process for the desired results.

Reason's to replace a light switch:
Over time the parts inside the switch wear down or break. This wear can make the device difficult or sometimes impossible to use. Its at this point where you want to swap out the switch for a new one.
Another reason to swap out the switch is to improve its utility or aesthetic features. Light switches come in various shapes, sizes, and colors, choosing the right one is up to you.

Replacing a light switch should only take 5 to 15 minutes.

Materials List:
-New light switch
-New faceplate (optional)

(Optional) Replacing the faceplate is not a requirement to replace the switch, but the faceplate needs to come off anyway so swapping it is easy.
Note: the faceplate screws into the light switch; make sure that these two materials match each other before beginning.

Tools List:
-Screwdriver
-Needle nose pliers
-Electrical tape
-Wire stripping tool (optional)

 WARNING: working with electrical devices with current running through them can cause serious injury or death.
This is a simple step, but it is the most important part of this entire process.
Go to your circuit breaker (it will look remarkably similar to the one in the picture) and turn off the power going to the light switch you want to work on.
Now you can mess up anything you want/need to on the light without any serious problems. The danger is gone; have fun with the rest of this tutorial.

A somewhat related 15 second video:
http://www.youtube.com/watch?v=AZVDm3gIhOI

With the screwdriver unscrew the screw(s) that hold the plate to the switch. This is done by rotating the screwdriver counterclockwise (if you're looking at the plate on the wall).
Sometimes plates stick to the wall or switch for various reasons. Once the screw is off knocking the plate from the sides will be enough to break it loose.

Now the screws holding the switch in the wall can be found on either side. A counterclockwise rotation with the screwdriver should take these out.

Know that there are three wires connecting to your switch: hot; common; and ground.
The hot and common wires carry the electric current while the ground wire provides a variety of different services (including, among other things, preventing the build up of static).

Pull the switch out. Even though the screws are gone the switch may still resist leaving its place in the wall. The wires provide this resistance but can be easily shaped. Bear in mind though that some of these wires are old and not as flexible as they may have once been, breaking them is possible.

Unwire the switch. Once the switch is far enough away from the wall you should have easy access to all of its sides.

Here is where it gets tricky:
There are two separate ways to wire the switch:
1. With stripped ends the hot and common wires can be inserted into the back of the switch -or-
2. With stripped ends the hot and common wires can be screwed onto the side of the switch
Depending on how the wires were installed is how you determine how they need to be removed.

Removal 1. Next to the hole where the hot or common wire has been inserted into the old switch there is another hole. This hole is for your screwdriver to go through and open the gate holding the wire in place. Simply press in with your screwdriver and pull out the wire. (Repeat for both hot and common wires). This leaves the ground wire to be unscrewed from its screw holder.

Removal 2. Simply unscrew all three wires (hot, common, and ground) from their respective screw holders. Remove these screws and free the switch from the wires.

Removal 1,2. (Optional). Cut the wires off as close to the old switch as possible. Once all three wires are severed the switch is free. This option may seem like the easier way to go, but in the end you'll end up doing more work on the wires than the other removal types.

Depending on the condition of the wires and style of the new light switch some more work may need to be done here.

If you removed the wires from the old switch like in removal 1 or 2 of the last step (5) then there isn't work to do here.

If you cut the wires or the wires don't have bare copper on the ends then you're going to need to strip the ends. 

You have a couple of options here. The two possible places you could've removed wires from are the same places you need to put the wires back.

In the back: straighten the wires and slide them into the holes indicated on the new switch. The gates will clamp down on the wire and hold it in place. The wire shouldn't slide in and out easily.

On the side: curve the wires around their respective screws (again, indicated on the switch). Make sure the curve of the wire is going the same direction as the turn of the screw. This way the wire will tighten around the screw as the screw is tightened. Make sure all three (hot, common, and ground) wires are well secured.

This is just an added safety precaution. The tape keeps any current from moving between the switch (and the wires connected to it) and the metal box that houses the switch in the wall.

Once or twice wrapped is fine.

Return the switch to the proper screwed in location. This step can be frustrating. The trick here is to try and get the switch in its place before doing any sort of screwing. Just push the switch in while moving the wires around behind it and eventually the switch should be good and lined up. When screwing in the two screws on either side of the switch be very careful as to not break the new switch. The devices are fragile and can break or crack making the new switch potentially less useful than the old one. Just go slow and make sure the switch can move to its final location before screwing anything in and all should be good.

Screw the faceplate onto the switch. After the switch is screwed into place the faceplate can be screwed on to it. Its easiest to match up the switch pole (on the switch) to the switch pole hole (on the plate) rather than matching up screw holes in both. Either way, once the plate is matched up, screwing the faceplate on is an easy task.

Turn the power back on at the circuit breaker and you're good to go.