A Man’s Belt Guide – What you need to know when buying a men’s belt. Flex the belt to make sure it hasn’t turned brittle or started to crack. Another good test of leather is to score the back very lightly with your fingernail — if a faint line appears, the leather is still soft and fresh. Old, hard leather will resist your nail. Better to invest in a calfskin/ lambskin leather (not bonded leather) with a snap so you can change out the leather when it gets old.