ભેળાં ત્યાં નથી જાણતાં, જાણશે જુજવાં થયે;

bhēḷāṁ tyāṁ nathī jāṇatāṁ, jāṇaśē jujavāṁ thayē;

Literally: Those together do not know, they will know when they are separated.
What it means: The value of a person or thing is realized only after they are gone.

Also said as

ગુજરાતી કહેવતસંગ્રહ (Gujarati Kahevat Sangrah) (1923) · read from the scan by machine — the Gujarati itself is unchecked · English is machine-made and nobody has checked it yet

Heard it differently, or know we've got the sense wrong? Tell us — that is exactly the kind of correction this needs.