Hello everyone and thanks in advance for any help! I know this has been asked a lot before and trust me..I have been reading posts and forums for days! However, I keep finding conflicting information and cannot seem to find everything I need in one place. First off, my specs: OS X Yoesmite 10.10.5 - 15 inch, Mid 2012 2.3GHz Intel Core i7 16GB 1600 MHz DDR3 NVIDIA GeForce GT 650M 512 MB So what I want to do is upgrade my hard drive to a SSD, then replace my optical drive with another HDD. Here are my main concerns: 1) TRIM - I get completely opposite opinions on TRIM during my research. Some say you need it, some say you don't. I've also read that in Yosemite 10.10.4 and on, you can activate TRIM (if need be) with a simple terminal command. Is TRIM something that I have to worry about at all? Or can I just move forward with my SSD upgrade? 2) What exactly will I need to copy my HDD now to my SSD? I keep reading about brackets, enclosures, Carbon Copy Cloner?? Can someone please help me figure out the tools I would need for this copy process? 3) I've also been reading that replacing the optical bay with a HDD can actually slow down the new SSD. Is this true? Is there anyway to know if this will happen before hand? As far as the physical process of replacing the HDD's, I've found good videos and picture descriptions on this. I am only being held back by the 3 points made above. (Also, I am looking at a Samsung 850 EVO for my upgrade. If anyone wants to throw in any advice on that, or if I should get OWC or Crucial, it would be much appreciated!!) Thank you so much for any help!!!