Let me start this post by saying, I am NOT a technical support person. Really, I recommend calling a professional for most issues, like accidentally deleting your files (or freeing up space). (Here's how to find a certified Apple Consultant.)
However, in this case, I happened to be available when this client called for help. He had, in a multi-tasking moment of haste, accidentally and somehow, deleted KEY critical documents from his MacBook in an effort to get his computer to run faster.
First of all, don’t let it come to this. (That's not helpful if it's already happened to you though, so read on.) Before you go deleting your files, set up Clean My Mac, an example of a tool that can help Mac users free up space, and delete old and unnecessary files.
WARNING! Don't Make This Mistake!
We downloaded a program called Stellar Mac Data Recovery, which had many rave reviews and all the right partner affiliations. We paid $99 for the base recovery service but alas - it didn’t work! All the files we recovered had become corrupt and were now taking up additional unnecessary space on the hard drive. (If you have used this service and had success, please let me know!)
In the end, we went straight to the web-interface of Dropbox, where most all of his files were stored. You can recover any deleted files from Dropbox within 30 days. Here are the instructions. And that, my friends, worked! Plus, once we dug through his email - which as had purposefully turned off so as not to get distracted - we had a nice email from Dropbox warning us that numerous files had been deleted…and did we want to restore?
Needless to say, I didn’t charge this client for all the learning and failure, but in the end, we got all his files back.
So now, after reading this post, do not pass Go, do not collect $200 until you register for an online backup service, like Backblaze. It will work in tandem with any local backup solutions you might already use, like Apple's Time Machine, or cloud-based storage solutions like Google Drive, Dropbox, OneDrive, or iCloud.