Answer first
A photo diary is the simplest way to judge change: once a month, take photos of your hairline, crown and parting in the same place, same light, same angle and with dry, unstyled hair. Compare month 1 with month 4 or 6, not yesterday with today.
Setup
Same spot by a window or under the same light, phone at the same height.
Angles
Front, top, crown and both temples. Ask someone to help with the crown.
Questions
Should I share photos with my consultant?
Yes, it helps them advise you.
Will you post my photos?
Never without written consent.