Hi there. Thank you for your question. Many people seem to think that if you layer your SPF products that you have longer/better protection, but this is in fact not the case. Just remember that the lower your SPF number, the shorter the protection time in the sun. So basically you would be protected at the SPF of the product with the higher rating (if you happen to have layered them). Regarding your question about needing to apply sunscreen over your products on the weekend; it really all depends on what you are going to do that weekend. If you are outside laying in the sun, then yes, you need to add additional protection. If you are going to be relaxing at home, indoors with no sun exposure then you can get away with not adding an extra layer.