SPF is a fairly “controversial” topic at the moment. There are a few things you should look out for. Firstly, ensure that you are using a broad spectrum SPF otherwise you are not very well protected at all (it should state this on the product). I always tell patients that it’s a good idea to use SPF’s of 30, minimum, otherwise you have to re-apply the product too many times throughout the day and it’s difficult to remain diligent in doing this, as it’s easy to forget or sometimes it proves to be an inconvenience. The general rule is that you will take the amount of time that it takes you to start burning in the sun, and multiply this by the SPF to give you the number of minutes that you are “protected” by the product. I highly recommend using an SPF of 30 or 50 if possible regardless of your skin type or colour. I can highly recommend the products made by Skin Medica, Heliocare and Skin Ceuticals for this purpose. There are many other good options, but as far as sun protection goes, I would say those are amongst the very best.