Safety glasses take a beating. Knowing when to retire a pair keeps your protection working the way it should.

1. They've taken a hit

If your glasses have stopped an impact, replace them, even if you can't see any damage. The job they just did may have weakened them.

2. The lenses are scratched or pitted

Scratches make you squint, strain and eventually take your glasses off. Heavily scratched lenses also scatter light, which makes glare worse.

3. The frame is cracked, bent or loose

Check the hinges, arms and bridge. A frame that sits crooked or slips down your nose won't protect you properly.

4. Side shields are damaged or missing

Side shields are part of the protection. If they're cracked, loose or gone, the glasses are no longer doing their whole job.

5. Your prescription has changed

If things are blurry, you're getting headaches or you're holding things further away to read, book an eye test. Your safety glasses should match your current script.

Running a team? A workplace program can track when each person's eyewear is due for replacement.