Replacing HD with SSD and I need some advice!

Thanks so much for your help, it's exactly what I was looking for! If I were to buy just the SSD and not the whole kit (I have a friend who already has all the tools), would I also need to get the cables separately?

And one more question (sorry for being obnoxious), is it always better to ADD an SSD instead of just replacing my normal HD with one?

It's a matter of costs and what is gained. If you replace your current HD with a SSD you tend to need a larger drive (1 or 2 TB). If you add in the SSD as a second drive you can use a smaller SSD (256 or 512 MB). But, this issue is moot if you have a bad HD and need to replace it. At that point it often makes sense to go with a SSHD than replacing it with a SSD as its more cost effective.

Don't get me wrong here I love SSD's, its just a matter of costs and the net gain when you are upgrading an older system like yours. Given its age are you likely to upgrade the system in a year? Then I would go with the lower cost direction. If you are hoping to get another two or three years then it might make sense but don't forget the system it self may have problems later on, either with what Apple does within its OS or an act of god killing your system.

Thank you so much for all of your advice! Surprisingly enough, there isn't anything severely wrong with my HD for being a 6 year old computer, but I'm sure it's only a matter of time. I'm mostly just looking to give it a little boost and prolong the life on it a little bit.

@popcorn -@danj - I was reading through this and thought I was getting a little senile because I didn't remember writing the exact words until I realized Dan said it and not me. We are of the exact same mind on this. If you chose not to replace the drive at this time, please get an external backup drive and use Time Machine to back up.