I thought those $35 automatic coop door openers were a total gimmick until mine saved my flock from a raccoon last Tuesday. | Backyard Chicken Keepers - nhfree.com
My brother talked me into getting a water leak sensor for under the kitchen sink. I figured it was just more junk to clutter up a drawer. Last month the pipe connection gave out while we were at work, and that little alarm screamed loud enough for the neighbor to hear. Saved us from a huge floor repair. Sometimes the simple tech is the only thing standing between you and a real mess.
Your brother is smarter than me. I once ignored a slow drip under my own sink for weeks, telling myself it was just condensation. Ended up replacing a whole section of cabinet floor. Those little sensors sound like a bargain compared to the smell of wet plywood.