How long do teeth gems last?

GEMS CAN LAST FROM 6 MONTHS TO (MY PERSONAL RETENTION TIME) 2 1/2 YEARS.

do they hurt to put on?

NOT ONE BIT. NO DRILLS, NO PICKS.

How do i remove them

a dentist willl be your first choice. AS MENTIONED THEY DO FALL OFF. sOMETIMES THEY LEAVE BEHIND SOME RESIDUE. wITH PROPER BRUSHING RESIDUE SHOULD FALL OFF ON ITS OWN.