2 - 4 horas
I had been considering installing a solid state drive in this machine ever since I purchased it in 2011. I finally went for it when I realized how nice the Samsung 840 SSD is.
This took me about an hour because I had a tiny bit of trouble putting things back together. The power supply cables got stuck between the two hard drives and didn't leave room for things to re-situate properly. After taking everything out and putting everything back in a few times, I finally figured it out!
Go slowly through the opening procedure - be observant. This way you won't get stuck when you're putting it back together. It was my first time doing a computer upgrade, so maybe that's very elementary advice.