system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do the clocks on all my devices fall out of sync?

Had a power cut three months ago. Set my oven, my microwave and alarm clock to match the time on my phone. After setting them they would have all been within 1 minute of each other roughly.

Three months on, at the time of writing this, my phone reads 10:10, oven 9:56, microwave 10:02 and digital clock 10:11.
gpt
The clock in each machine is designed around a resonator - a small device which vibrates and its vibration is measured and counted to keep time. This is much like the pendulum in a clock.

Now these things are precise. Higher quality ones can get very precise. They are not, however, perfect, and every one will be cut slightly different. A different cut means a different frequency, and a different frequency means that one will count faster than another.