Hebrew birthdays explained: why the civil date changes
A Hebrew birthday is anchored to a Hebrew month and day. The civil date is helpful for planning, but it is a yearly conversion rather than the source date itself.
Save both dates, but know which one is primary
When possible, record the civil birth date, the Hebrew birth date, and where each came from. That gives relatives a familiar date to recognize while preserving the date the family may use for observance.
Leap years are part of the story
The Hebrew calendar includes leap years and an additional month. Those details are why a date should be stored as a calendar-aware value, not as a note somebody has to recalculate by hand every year.
Use reminders to invite, not merely notify
A family reminder can do more than mark a date. Include a photograph, a voice note, or a prompt for relatives to add what they remember about that person.