What are guitar scratch plates made of?

Most guitar scratch plates are made of plastic although they can be made from a number of other materials such as metal or wood.

Do pickguards affect sound?

As with most parts of a guitar, pickguards can affect sound but changing one for another likely wouldn't be as noticeable as something like changing the body wood.

Do you really need a pickguard?

Not all guitars have been designed with a pickguard but many iconic guitars such as the Stratocaster and Telecaster make use of one to help protect the surface of the instrument from unwanted play marks.

Is changing a pickguard easy?

Changing a pickguard can be very easy if you purchase an official one that is compatible with your guitar. It can be as simple as unscrewing the old one along with the control pots, pickups and switches then replacing it with the new one. One thing to check for is the number of screw holes and their alignment as this can differ depending on the model.