e.g., my home is always vacuum-proofed. It automatically runs through all rooms except for the bedroom at night, finishing just before my alarm clock rings, then vacuuming the bedroom an hour after the last person's alarm clock has rung.
This way I never actually notice it, but the home is always perfectly clean as if by magic.
Similarly, if you use separate dishwasher detergent, antisurfactant and salt, and properly dial in your water hardness, it'll be able to clean everything no matter how dirty the dishes are. Including dried-on tomato sauce. Just put the dishes in, and they'll be clean the next day.
Of course it takes a bit of effort to set this up, but then it just works for a long time.
Similarly, I'm a big fan of handwriting software with care & focus on quality, which takes a bit longer at first, but then allows you to trust the software to continue running for years to come.
And then of course, all the cat's toys.
This might be the next thing the robot vacuums all start working on. One has already released a first version: https://www.youtube.com/watch?v=GykaEgNkkVQ
Sure, it's not perfect, but it's still really convenient.