Trimming your cat's claws blunts the sharp tips, protects your skin and furniture, and stops claws growing into the pads, which is common in older cats that scratch less. It's not a substitute for scratching posts, which cats need to stretch and keep claws healthy.
The quick is the pink area inside the claw that contains blood vessels and nerves. Cutting it hurts and bleeds. In cats with clear claws it's easy to see; cut only the sharp hooked tip beyond it.
Most cats tolerate nail trims well if they're introduced slowly and kept very short.
