I've only read the OP but I'll read the rest of the thread shortly.
We burned. My parents took the approach sometimes that a bit of sunburn would give you a nice tan and then you were protected from the sun. This approach led me to being so badly burned as a toddler that, in their words, I was essentially one big blister.
They only started using Sun cream from the alte 1980s onwards when, as a family, we had such severe sunstroke the hotel called a doctor and apparently (this is gleaned from the joyful retelling my parents do, decades later) he told them off for such stupid behaviour. They have a series of photos, we look like we were grilled for 8 hours. Which we were, to be honest.
After that we had factor 15 or 20 slapped on us, but only on foreign soil. Because UK sun doesn't burn 🙄i don't remember it being applied unless we were spending the day on the beach and only then only if we were visibly red and burnt. Again, being sunburnt led to a tan and that meant we were protected, according to perceived wisdom.
When I send my DC to stay with my parents, they are supplied with factory 50 and baseball caps. The kids have been applying their own suncream since they were at nursery. My parents laugh, a lot, at my over-the-top "barrier cream". But I don't want the kids to have sun damage. We all burn easily and I do my best to protect them.
DH has a skin condition that benefits from not using any SPF but he also burns, so he uses it more than not.
So my recollection is summers being nicely crisped up, and then having some level of a tan afterwards which my parents approved of. Nobody wanted a peely-wally child cutting about the place.