5 - 30 minutes
I replaced the original 160GB HD on my Mid 2009 MacBook Pro as I was running out of space and was facing performance issues. Initially I was looking to purchase a flash drive however the price point and amount of storage of a hybrid drive were hard to pass up.
The repair went about as smooth as it could go - about 30 min total. I used the iFixit tool so I had everything I needed. The instructions were clear and spot on, very easy to follow.
Purchase the tools with the replacement kit, its worth the extra money. I used 3 different screw heads. I don't usually say this but follow the instruction as they are well written with very good pictures. So far the drive has performed well and I'm very happy with its performance and ease of install.