I use at least spf 30 because, hereditarily, I tan very fast. Don't get me wrong, I love a tan, but I need something to shield me a little better than spf 15 would. That way I can spend a longer time outside without feeling like suddenly none of my foundation will blend into my skin anymore lol!
btw, ahyee, there's plenty of spf 30+ facial moisturizers on sephora.