Dumb question, but if I wanted to check my spark plugs myself and didn't have a 12" extension for the socket wrench like that mechanic had, would I need to take off my cylinder head cover to get to the spark plugs?

 

Squeezer, I don't know about you but I certainly wouldn't be taking my head cover off. I had a 6" extension for my socket set and that was more than sufficient - the cost of an extension is around $5 whilst you would spend considerably more in time and effort taking off the head cover without talking about costs of spares e.g. new head cover gasket.

In addition, even if you took the head cover off there is a possibility that the plug tunnels may still be too long and you'd still need an extension.

 

Duct tape the plug socket to the extension so you don't loose it down the hole. A small piece around the mating surface in between will do.