I carry 9-10 discs in my bag; usually 9, leaving room in case I find a nice uninked disc on the course. Why? It's all my bag holds. My mom made me a bag similar to a double nutsac, but a bit nicer. I love it, and it keeps me from carrying too many discs. Also, I don't carry any duplicate molds, so that keeps the count down too.
This does cover every shot for me, but I always feel like I need another miracle fairway driver. Don't know why that is; maybe just because so many new ones are coming out lately...