Am I the only one who thinks a $25 stud finder beats knocking on drywall?
When I first started running cable back in 2009 around Dayton, I used the knuckle tap method for every wall. Then a guy on my crew handed me a basic stud finder and it cut my locate time from about 10 minutes a room down to 2. The difference was night and day once I started fishing through finished basements where guesswork meant patching holes. Still keep one in the van and one in the truck now. What's your go-to trick for finding studs behind old plaster?