I'm 45 and have been using spf on my face every day since I was in my late teens / early 20's. I think that when I was in my earlier teens the info about sunscreen and skin ageing just wasn't as known and that very few moisturisers or foundations actually contained any sunscreen at all and not many would have put (sun tan lotion) on their face in winter! In fact I remember when most sunscreens seemed to be spf 6 and my parents using tanning oil in the 80's. Perhaps people from different countries where it is sunnier had different attitudes to spf but in the UK I don't think anyone was really wearing it daily until the early 2000's where they?
I recall being an outlier amongst my peers for caring about spf when I was in my 20's in the early 2000's and that people even thought the spf 15 I was wearing in winter then was excessive, never mind the daily spf 30 - 50 I was wearing daily by the mid 2000's. Even at that point when spf was more commonly found in make up and moisturiser it was and spf 15 and mostly you weren't applying that in a thick enough layer for it to be effective.
Am I wrong now in thinking that most people are wearing spf 30 - 50 on their face and exposed skin everyday even in winter? When did you first start to take notice of how important sunscreen was for your skin? Do you where it regularly and think it has made a difference to the quality of your skin as you have aged?