2 - 5 Minuten
Basically, because I was bored with the old system so I upgraded everything and I finally had the time - literally jumped from snow leopard to yosemite! It started with installing higher ram then figured out it was easy enough to install not just a new hard drive but a dual one. Thanks to you guys with your clear cut instructions it made everything possible.
Everything went well. My only problem was I found a stripped screw in the primary hard drive slot panel and I don't know how to fix that. It must have happened from the last time I installed a new hard drive to replace the old one. Now I can't put an SSD in there so I just placed the SSD into the optical drive bay instead. The actual repair only took me less then an hour ( I'm a beginner at this). Installing the OS X took longer :)
If you feel like you can do it , you can.