For no important reason really, I took a look at my Activity Monitor and noticed I am using 10.42 GB of memory. Among my open applications are Safari, Mail, Calendar, and Preview. There are a few others that run in the background; however, nothing too intensive as far as I can tell. I certainly do not experience any slow down or stutters. In fact, I can't remember the last time I saw a beach ball. I just thought it was interesting that my system uses more than 8 GB of memory on a relatively light load. I also find it interesting that the Activity Monitor is not optimized for the Retina display. The text and icons within the window are pixilated. So, for those wondering whether you will ever use more than 8 GB of memory, I'd say it's very likely. Do you need it? Probably not; however, it can find a way to put it to good use.