[chao-]

I forget where I first heard it, but "Dates are not real. Only times with zones are real."

When you need to be precise, you specify a time and a zone.

When your application has users in different geographies, you need to be precise.

Displaying the date attached to a time is a presentational convenience. Only the time is real.

[OptionOfT]

Example of dates not being real:

You celebrate your birthday on January 5th, whether you're in Hawaii or New Zealand.

You might get texts from friends & family earlier and later than that.

Outlook had a funny bug where when you stored a birthday on a certain date (which is then an all-day event), it would shift that all-day event by x-hours when you changed timezones.

[bryanrasmussen]

>When your application has users in different geographies, you need to be precise.

depends how important it is. app for tracking celebrity hairstyles forego precision for easy understanding, stock markets precision needed.