I'm still running 10.8.5 - I run my system very, very hard, typically 20-30 Apps simultaneously with multiple Fusion VMs, and 50+ tabs in the browser, all three

I'm still running 10.8.5 - I run my system very, very hard, typically 20-30 Apps simultaneously with multiple Fusion VMs, and 50+ tabs in the browser, all three browsers, running, Aperture, Full Office suite - and I've never run into an issue with memory. Unless you are running XCode, or Video Editing, or some of the heavy Adobe Suite/SomeOtherSpecializedNicheWorkstationApp - you really don't need more than 8 GiB on OS X (at lease as of 10.8.5). I'm guessing that SSDs and swapping really changed the game around virtual memory performance on Mac laptops.