Interesting. I've never been that worried, my skin doesn't burn easily even though I'm very fair-skinned and live in Spain and often hike outdoors.
I just hate that SPF stuff on my skin. It makes it sticky and makes me feel dirty. Instead I just try to avoid burning. I do bring some for when it does start but it almost never does. What I do to avoid it works well enough.
What I tend to do is just take the shady side of the road wherever possible and for the rest of the time just not worry too much unless I really feel I start getting burned. I check that by scratching my skin with my nail, once it starts burning it feels sharper. Then I'd put on the lotion. And by the time I get home my skin will be slightly red but not seriously burned. Which is pretty rare because I tend to tan naturally. By the time spring starts I already have a light brown shade and it protects me during summer. Most of the time I don't even burn at all.
What I do think is bad is someone living in a dark nothern country going on holidays for 2 weeks and spending 2 weeks lying on the beach in the full mediterranean sun. Sunblock or not. My ex used to do that and she got totally burned on the first day even with the sunblock and then spent the rest of the weeks complaining :) I used to live in such a country and I was always more careful during holidays.