They're 4&2. I'm always hot on putting sun cream on, making sure they're not out for a long time in the heat of summer, all the general recommendations with sun safety.
I've heard spf50 sun cream blocks a lot of the goodness of the sun whereas lower spf can still let that through.
So, given I stick to the recommendations of staying safe in the sun, aibu to use spf30 (with 5 star UVA rating)?