Do not check datetime too often!
Use time.monotonic even if your expensive operation takes long time!
Timezones all over the world in one look
Timezones within years
- don't invent your own timezone
- don't hard code any rules
- keep your libs up-to-date
- convert from local time to UTC as soon as possible (be precise or guess)
- convert from UTC to local time as late as possible
- follow your government's intentions to modify your time zone and inform firstname.lastname@example.org
- avoid timezones if you can!