Alexia Mckenzie is surrounded by chronic time wasters. They check their mail when they get home. (Typical.) They answer the door when someone knocks. (Lame!) They even do their own laundry. (Why?) McKenzie wants none of this.

If there's a way to eliminate an inefficiency, McKenzie will find it. She installed a sensor that tells her when a letter arrives. A webcam livestreams a view of her doorstep to her phone, so she always knows who's knocking. As for laundry, she doesn't bother—don't you know there's an app for that? After years of testing and tinkering, McKenzie has transformed her life into a smooth operation managed by apps and hardware. She Lyfts to work, keeps a tablet open to Instacart on her fridge (she never runs out of eggs), and waters her plants remotely. Rigging all this stuff can get complicated, though, so she's taken optimization one step beyond: McKenzie had a tattoo artist implant a magnet under the skin of her left hand to hold metal parts as she works. “I'll be fiddling with a wire or a screw, and I'll be like, live there for a moment,” she says, pointing to the spot. Then she shows off, using another magnet to make the one in her hand spin in circles: “I can make it dance!”

Now McKenzie, who works for a hardware design firm in San Francisco, is helping others streamline their lives. Her mom doesn't like getting out of the shower, so McKenzie made her a heated bath mat to ease the transition. When people invaded a local community center, she set up a lock system and distributed keycards to the other members. Of course, McKenzie doesn't need one herself. She has a radio tag embedded next to her magnet—the key is always in her hand.

Smart House Rules

Here's how Alexia McKenzie automates her life.

1. Her DIY “brainbox”—its speaker shown stuck to her underskin magnet (above)—emits sound waves that help her fall asleep.

2. Her fan switches on at a specified temperature.

3. Instacart stays permanently open on her fridge.

4. A homemade irrigation system waters her plants.

5. A webcam tells her who's knocking at the front door.

6. A sensor pings her when a letter arrives.