I work in embedded.
We have to do this on our own.
It is every bit as painful as it is made out to be.
A common problem that I don't see discussed much is the difference between recording when a time took place (just record and store it in UTC!) and then translating that into what the user expects to see. This is especially hard if you have information that should be grouped into "days", and a use case where the user changes time zones but may expect the same "relative to originally recorded time" to be shown when viewing past events.
A nightmare case.
