I have implemented an event ticketing system. One of the things I (fortunately) realized early was that storing times with timezones would be a problem: Events

I have implemented an event ticketing system. One of the things I (fortunately) realized early was that storing times with timezones would be a problem: Events get moved, occasionally across timezone boundaries. If you store epoch-instants, then the logic for "set location" would also have to update every timetsamp in the database associated with the event. IMO, in a database you should store the "natural" representation of date-time as your users think of it. Sometimes (like your alarm clock), it's timezone-less concept. Sometimes (like a sporting event) it's a combination of datetime + location. Sometimes (like historical events) that's a fixed instant in time. Recognize which is which and model appropriately.