How long does a night guard last — and when should you replace it?

Realistic lifespans

For a custom plate: soft guards typically 6–12 months, hard guards typically 12–18 months, sometimes longer for lighter clenchers. Heavy grinders should expect the shorter end of both — and if you're wearing through a hard plate in under a year, that's information about your force, not a defect.

Boil-and-bite guards from the chemist are a different category: weeks to a few months before they deform or perforate.

The five signs it's time

• Thin spots or perforation — hold it to the light; if you can see through where you bite hardest, its protective job is nearly done
• Cracks or stress lines — replace now, not soon. A cracked plate concentrates force instead of spreading it
• It no longer seats properly — a plate that rocks, feels loose, or needs pressure to sit has lost its fit, and a loose guard can aggravate clenching
• Persistent smell or cloudiness after a proper deep clean
• Your bite has changed — new fillings, crowns, extractions or orthodontics all change the fit your plate was made for

What shortens a plate's life

Grinding force is the main driver, but the avoidable ones matter: heat (hot water, dishwashers, car dashboards — warping ends a plate instantly), abrasive toothpaste, and storing it damp. Our cleaning guide covers the routine that genuinely extends life.

Don't limp on

The gap between "worn out" and "replaced" is the risky part — those are unprotected nights for teeth that have already proven they need protecting. If you know you replace on a rhythm, a replacement plan removes the decision: your scan stays on file and a fresh plate arrives on schedule, without redoing impressions.