High SPF can trick you into staying out too long.

Yes. It’s not the sunscreen’s fault, but the math doesn’t work the way people think.

SPF 50 blocks about 98% of UVB rays. SPF 100 blocks about 99%. That’s a 1% difference in protection. But people see “100” and think they’re invincible. So they skip reapplying, use less, or stay out an extra hour. That’s how you get burned.

The real problem is coverage and reapplication. Most people apply half the recommended amount, so even SPF 100 effectively becomes SPF 30 or worse. And high SPF still doesn’t protect well against UVA unless it’s broad spectrum.

If you buy SPF 100, treat it exactly like SPF 50: apply generously, reapply every two hours, and don’t assume you can cook in the sun all afternoon. False security is the real danger here, not the number.