Take away your shears and you are out of business. But it’s not simple enough to pick up a trusty pair that has been kicking around the salon since before you were born. Nothing can wreck your career faster than repetitive stress injuries such as carpal tunnel, which is why it’s essential you select the shears that are right for you—think of them as your best friend or sister.

“The right shear should fit like a glove,” says Marc Milman, owner and founder of Washi Scissor Co., which has been making scissors for 30 years. “In…