I dont know if there is really a correct SPF. I think its more important to use sunscreen correctly. There isnt that much difference between an SPF 15 and 30. Im not sure about the higher ones. But no sunscreen in 100% effective, and they dont mean you can stay out in the sun indefinately. They prolong the time it takes for yo u to burn, but you cant expect them to work all day, even if you u reapply them. You should still limit your direct sun exposure where you can. Its also a good idea to note what conditions your sunscreen was tested in. For example, in New Zealand its best to use sunscreens specifically approved for use in this country as our sun is a lot harsher than other parts of the world due to lack of ozone.
It depends on your natural skin, if u have pale skin then you should wear a higher SPFid say for children under ten SPF 40 take no risks, they font need a tan at that age, 10-16 i would say an SPF of 35-25 and adults can choose for themselves vut id recomend 25.
Well I use SPF 50 on my face because my cheekbones burn really easy, but I don't put sunscreen anywhere else. So I guess it's just a personal choice.
I have fair skin, and have tried factor 30 but I still burnt so I wear 50 now and that really helps and I hardly ever burn when using it.
stronger the better. they say that after 30 spf there's really no difference as long as you use as directed.