In 2011 I bought a new MacBookPro. It was an i7 model, with 8GB RAM and a 128GB SSD, which was the smallest option at the time.
It's been fine, but eventually I ran out of disk space and even using my iCloud account as my work-disk didn't really solve the basic problem. It kept the system chugging along, but with "only" 15GB of free disk space, performance was somewhat compromised.
So I finally decided to upgrade to a 500GB SSD. When I checked what options were available from Crucial, I was delighted to discover I could upgrade my RAM also - I had forgotten I could do this. So I bought 16GB of RAM along with the 500GB SSD and waited for the Royal Mail to do its stuff.
In order to provide the best possible user experience, Apple are pretty stingy when it comes to disk drive upgrades - in fact they don't do them - and make no guarantees that a Mac that's been upgraded with a 3rd party drive will work.
A key feature needed to maintain SSD performance you need to enable something called TRIM, and to do this, you have to go into Terminal and type: "sudo trimforce enable", then say Y to the scary message that's displayed on screen.
But I'm getting ahead of myself.
First I made sure my bootable backup drive which I created with SuperDuper did in fact boot my system up, which it did. I then made sure all my work files were safely copied over to my iCloud account. I wasn't concerned with making a fresh backup of everything onto my external bootable HD - all my apps could be re-downloaded in any case and besides, I didn't ned a fully working system on the external HD which would be slow.
Then I powered down my Mac, disconnected it from the mains, and opened the base using a tiny Philips screwdriver. Taking the baseplate off revealed not a lot of spare space, but the major components were readily identifiable; battery, cooling fan, optical drive SSD and RAM chips.
I then disconnected the battery from the motherboard to make sure nothing was charged up.
The RAM chips - 2 x 4GB - popped out easily enough, and the new SIMMs slid into place with a satisfyingly firm feel. I wondered whether I should reassemble everything and do a test startup, but decided that I may as well continue.
The 128GB SSD was also easy to extract - there was a clamp held in place courtesy of a couple of Phillips screws. Once this was off, the drive unit itself came out in my fingers - being careful of the control ribbon, which then needed to be unplugged from the drive.
In order to prepare the new SSD for installation, I transferred the 4 "holding bolts" (Torx headed bolts) from the sides of the old drive to the new, attached the controller ribbon and slotted the new SSD into place. Re-fixed the clamp, reconnected the battery,, replaced the cover, connected to mains, attached external bootable disk drive and pressed the on button and... bonggg! The satisfying boot up bong sounded and I was presented with the log in screen.
The only visible drive to the system at this point was the external bootable drive, once I'd logged in and opened Disk Utility, I could initialise the new disk drive. Having done that I then downloaded ElCap from the app store and installed it on the new drive.
The very first thing I had to do after the initial system setup routine after first login, was to open Terminal in Disk Utilities, and type in the "sudo trimforce enable" command, and the system rebooted. I logged back in and downloaded all my apps from the app store, including ones I'd previously deleted just to create the minimum working space on my old drive.
It's amazing to have 16GB of RAM and 500GB of storage in a laptop! Despite Apple's cautionary notes, it's all working really well, and with all that RAM, Safari is blindingly fast. I have yet to do some meaty work with the "new" machine, but it feels like.. a new machine.
My girlfriend also has a late 2011 MBP, albeit a 13inch one. Her machine is running two versions of OSX behind the curve and needs some attention. The config of her machine is 4GB RAM and 500GB spinning HD. The plan, when I get hold of her Mac, is to replace her 4GB RAM with my old 8GB RAM and although her hard drive is 500GB, to replace it with my old 128GB SSD. This won't be a problem as she's only used 50GB or so of disk space - but the performance and resiliency increase will be worth it. We'll both have effectively new machines, for the princely sum of £200!
This then leaves what will be her old 500GB spinny disk. I have a plan for that too - I'll replace my hardly-ever-used-these-days-internal optical drive with it, and use it as an internal TimeMachine backup drive.
The only thing left over at the end of all of this will be the old 4GB (2 x 2GB) SIMMs from Virginie's Mac. I have no plans for these.