If you store it in UTC, it becomes obsolete when the rules change for that location. If you store it in the local time, it becomes obsolete for other timezones

If you store it in UTC, it becomes obsolete when the rules change for that location. If you store it in the local time, it becomes obsolete for other timezones (think the timezone of the traveler before they leave). If you store both UTC and the local, then one (of the 2) becomes obsolete, but recoverable assuming you can scrub the data. However, you must know which is correct based on the rules change itself.