A practitioner will frequently be told something like this, “My mother knows my birth time was a quarter of an hour either before or after 10 am, but she can’t be sure which”.
That sort of doubt can be resolved quickly and easily by Age Harmonics. Get three or four important events in the life of the subject, with their dates, and set up the corresponding Age Harmonic Charts for both birth times. Inspect the Charts for the relevance of each one to the events. They will be widely different, and the practitioner will have no difficulty in deciding which is the correct time.
The type of events normally most useful are: Marriage, first job, birth of a child, acquiring a house, surgery, accidents, death of a parent, long-distance travel, a career advance.
Here is a case that occurred in my own practice—a woman born in Lima, Peru, on December 5, 1967. Her mother said she was born either 15 minutes before or 15 minutes after 7:45 am, that is either at 7:30 am or at 8:00 am.
Important life events were:
25 May 1987 – Formed Relationship

It is clear the 7:30 am Chart is by far “the winner”. It has
Jupiter on the Cusp of the Love & Romance House sextile to Venus (Love & Union), while the the Ruler of that House, the Sun, is conjunct Uranus
(electric attraction).
15 Jan 1990 First job.

Here again, the 7:30 am Chart is strongly indicated: The Sun (business or profession), is on the Cusp of the House of Work, while Jupiter and the N.Node occupy the House. The Ruler of the Ascendant, Venus, disposits the Sun and is linked to it by square Aspect.
The 8:00 am Chart has no indications of a job.
22 Feb 1999 Hip replacement

In the 7:30 am Chart, Jupiter (the hip) is conjunct Saturn (the bones) and rules the 8th House (surgery) and is opposite Pluto (replacement of body parts).
In the 8:00 am Chart the Aspects point to something quite different—overseas travel (Moon in the 9th House opposite the Moon) and trouble at work (Saturn and Pluto straddling the MC).
1 Sep 2003 Broke ankle.

The 7:30 am Chart has Scorpio rising. Ruler Mars rules also the House of Illness and is conjunct its Cusp. Saturn (bones) opposes Mars (injury). Uranus squares the Sun in the 6th House (a wrench).
The 8:00 am Chart the Sun and Mars in the Midheaven trine to Uranus, referring to
a quite different matter—the job.