Always apply enough and In advance - if you can, 20 minutes before sun exposure, as it needs to be absorbed by the skin to offer the maximum protection and never forget that even on cloudy days you are exposed to damaging ultra-violet radiation. When it comes to the SPF value always go higher as you need to take many factors into account - the intensity of UV radiation levels vary at different times of day, your genetic make-up, if you are in and out of water etc.
What SPF is best to buy - the SPF (Sun Protection Factor) rating system is essentially a measurement of the length of time a sunscreen will protect your skin against UVB rays (the ones that cause sunburn). Higher SPF values do increase the length of time you can spend in the sun but only incrementally, so anything above SPF 50 does not dramatically increase the protection levels.
The most important factor is to use a broad-spectrum sunscreen (this means it protects you from UVA and UVB radiation) and never under SPF 15. Also look out for key ingredients such as selective UV filters, which repel - or reflect - the UV rays rather than absorb it - and skin conditioning moisturizers to replenish the dryness that is caused by the sun.
QMS Medicosmetics Cellular Sun Shield SPF 50 has a balanced UVA/UVB protection and a DNA-repair complex designed to provide protection against sunburn and premature skin aging. The level of SPF in this formulation allows the protection to be highly effective even in extreme conditions for example the mountains, tropics and on the sea.
Remember any sunscreen is only as good as the application so take a few minutes to apply thoroughly to all exposed areas.
For the Kids - the rules are very simple, the first one being that you must always apply full sunblock on children and with babies you need to take extra care particularly before 6 months old when you should keep them out of the sun as much as possible. Just one case of sunburn in childhood can increase the risk of melanoma so it is important to always use a high protection sun block, which you reapply often especially if they are in and out of water. Children also tend to rub their eyes so choose a sensitivity appropriate sun care. Protection does not stop at sunscreen, make sure they have good sunglasses that will filter out the damaging UV rays, wide brimmed hats are good for all ages and always remember to keep up the hydration levels, water is best.