There are also RTC chips out there that will monitor a tamper-detection switch [1] and keep a timestamped record of the switch changing. Which is nice because

There are also RTC chips out there that will monitor a tamper-detection switch [1] and keep a timestamped record of the switch changing. Which is nice because the manufacturers have made sure it'll run for years on end from a coin cell battery. [1] https://www5.epsondevice.com/en/products/rtc/rx8901ce.html https://www5.epsondevice.com/en/products/rtc/rx8901ce.html