Must Have Criteria are qualities that you can't live without. Selecting this checkbox ensures that every profile in your search results contains one of the selected values.

For example, if you select Black and Blue for Eye Color, and you specify Eye Color as a Must Have Criteria, then the eye color of all profiles in your search results will be either black or blue. If you don't check "Must Have," then people with black or blue eyes appear at the beginning of your search results, and people with other eye colors appear further down.

So if you prefer that your matches have blue eyes, but are open to other eye colors, then don't check "Must Have."

Don't be too picky! Selecting more than six Must Haves may limit your search results too much.