Shoutout to the installer in Tulsa who showed me the magnet trick for finding studs behind plaster
About 3 years ago I was doing a panel swap on an old house in Tulsa and could not find a single stud behind this thick plaster wall. An installer with 20 years on me watched me poke around for 10 minutes, then pulled a rare earth magnet out of his pouch and slid it across the wall until it stuck on the nail heads. Whole job took 15 minutes after that instead of the hour I had budgeted. I have kept a stack of those little magnets in my van ever since and they have saved me on at least 30 jobs. Your mileage may vary on lath and plaster versus drywall but it works on both for me. Anybody got other tricks for mapping walls in these old houses before you start drilling?