Generally most of my electronics that contain a microcontroller but no internet have been bug free. I think part of this comes from the much smaller testing su

Generally most of my electronics that contain a microcontroller but no internet have been bug free. I think part of this comes from the much smaller testing surface - my old vacuum cleaner has one button for power and one dial for suction power, so it's quite simple to write a bug-free implementation. Same for my dishwasher, laundry machine, etc. They generally come with a very limited number of inputs, and a microcontroller that runs through a state machine based on the inputs.