There are a lot of myths which have been debunked regarding sunscreen and UVA and UVB.
For one, everyone should protect against melanoma – regardless of skin colour.
To keep out the harmful rays, spread a serious amount of at least SPF 15 to 30, but less than that or more than that isn’t recommended: the former for not being protective enogh, the latter for just being more expensive and not doing any more.
THERE IS NO SUCH THING AS WATERPROOF.
After a couple of hours of swimming, or not, reapply. Because sweating also does the trick. Even with “waterproof” sunscreen.
Stay in the shade is the best advice. Besides, who needs a tan? And if you must be in direct sunlight (for sports or swimming in the sea, whatever) try to do it before 10 a.m. and after 4 p.m.
Tip for women and metro’s (JK): it has been proven that all the anti-ageing creams are crap – forget about the Q this and anti-oxidant that – go with sunscreen. It has been proven that pretty much any moisturizer will work the same, which means not much, but sunscreen will definitely do wonders for your face – in saving it from what would happen much faster if you DO NOT apply it.
Use a cheap moisturizer, your Clarins works the same as your Nivea; then apply a good sunscreen – that will save your face from the ravages of time much better than a 300 dollar moisturizer.