Over 80% of sunscreen performed below their labelled efficacy (2020)

I started wearing a cheap sombrero while doing yard work in the summer. It's a game changer. Going to Mexico this winter and hoping to find some nice ones to bring home.

This summer I started following the lead of my tour guides in Mexico and the local day laborers. Both favor spandex arm sleeves that are remarkably breathable and can be put on or removed as conditions change. They have been great for hiking and kayaking, though the maker warns that they aren't as effective if they get fully wet.

I live in North America and use full sleeve sun hoodies for hiking in the summer. I sweat a lot but these hoodies are breathable enough that it doesn't bother me. So I need to apply sun screen only on my palms and fingers. And paired with a wide brim hat, I can get away with applying sunscreen only to the lower part of my face and neck.

Applying sunscreen to your palms? And if your still applying it to "the lower part of my face and neck" what's the savings from doing the upper at the same time (plus this will get your palms & fingers too, if that's your jam)?