Your vehicle’s spark plugs are responsible for delivering an electrical current to your engines combustion chamber from the ignition system.
Basically, just like other parts of the engine, they make the car run.
However, just like oil and air filters, they need to be periodically replaced. The metal that surrounds the spark plug deteriorates each time you run the car, so for a typical car you usually need to replace them every 20,000 miles or so.
But changing your spark plugs is actually an easy process, and making it a DIY job will save you a good chunk of cash in the long run.
Check out this visual tutorial from Wikihow on the proper steps you will need to take to get the job done right!