SPF 30 and SPF 50 are closer than you think.

SPF measures UVB ray blockage, not time. SPF 30 blocks about 97% of UVB rays, SPF 50 blocks about 98%. That extra 1% matters if you burn easily or spend hours in direct sun, but for most people SPF 30 is enough if you reapply.

The real issue is that nobody applies enough sunscreen to get the labeled protection. You need about a shot glass full for your body. Most people use half that. So the practical difference between 30 and 50 shrinks even more.

Wear whichever one you’ll actually apply and reapply. That’s what actually protects you.