Swapping out spark plugs is, next to changing your oil, one of the most basic, straightforward bits of maintenance you can perform on your car. Spark plugs go bad over time, so it's important to keep them fresh so your engine continues to run well. Inspecting spark plugs is also a good way to check on the health of your engine. That's why whenever I'm doing a job that involves spark plugs, I bring a set of spark plug sockets.
Spark plug sockets are—you guessed it—sockets designed specifically to handle spark plugs. They come in sizes that fit snugly around most spark plugs, and good ones have magnets and a bit of rubber inside to keep them from falling out when you're removing or installing plugs.
Any DIYer tackling a spark plug change can benefit from using spark plug sockets. Unlike normal sockets, they actually grip onto the plug, making extraction easy. With a good spark plug socket, you don't have to worry whether the socket will drop the plug as it's coming out of the engine's head. Some spark plug sockets have built-in extensions, so you don't have to stress about the socket separating from your ratchet mid-replacement.
I've had a few cars where it would be next to impossible to use regular sockets to get spark plugs changed. My V-10-powered M5 and V-12-powered 850i projects come to mind, as they had especially tight engine bays. Not having to stress about the socket dropping the plug or disconnecting from my extension through a nest of wires and hoses made plug jobs way, way easier.
Because spark plug sockets are just slightly different versions of regular sockets, they're not astronomically expensive tools. Gearwrench will sell you one for just over $10 on Amazon. I have a three-piece set of Gearwrench spark plug sockets, two of which have swiveling extensions for easy use. That'll run you just over $60 on Amazon right now—totally worth it if you're checking or changing your plugs more than once a year. Gearwrench also makes a set that comes with two sockets and a funky ratchet, in case your spark plugs are in hard-to-reach locations.