I wrote here about my plan to upgrade my MacBook Pro from 2011. I read about it in Business Insider how I could just buy a solid state (SSD) hard drive and upgraded memory (RAM) for $200 in total and my machine would perform like a champ again.
My friend Brian knew what to do and it was very easy... it took a few hours to make a copy of my mac drive onto the SSD but other than that he said it was about 10 minutes with the case open and a couple of screws to get the job done. Now it is super fast and you don't have to watch the excel icon "bounce" for 30 seconds while it waits to load up if you have a web page open. The new Mac OS automatically encrypts everything and I started using a third party anti virus scanner and both of these changes contributed to my previous performance issues.
Solid state drives are a thing of beauty... compared to mechanical drives, not only are they exponentially faster, but they are far less likely to fail because they don't have any moving parts (or hardly any, I'm not an engineer).
When you have a computer - the question is - what do you keep and throw away out of the original boxes? When we swapped out the drive Microsoft came up and asked for the product key on my Office for 2011. Luckily I kept that key (about the only thing left from the 2011 Mac purchase, I long since threw away everything else) and then Office is as good as new.