If you have never had your Outlook crash or suddenly lose messages, appointments, etc. you are fortunate.
No matter how carefully you monitor your system, those things WILL happen, and recovering your data from a backup is not always possible, whether because the backup isn't current or because what you need is buried too deep and is inaccessible without "restoring" other files that you don't want to restore.
I suggest you make a habit of doing a "copy" backup of your Outlook data files on a regular basis (maybe as frequently as every 2-3 days, but no less often that once a week if you use the program all the time).
To do this, locate the relevant files (normally "Personal Folders.PST" and "Archive.PST"). You may look first in your C: drive under \\Users\[your name]\AppData\Local\Microsoft\Outlook. OR you can search for *.PST files on your system. (Don't be surprised if you find several; just look for the ones that have the newest dates.)
Create a new directory, either in the location where you found the PST files or in another location that works for you. Call it "Outlook Save" or any other name that you will remember.
Then, as often as you wish (or have time for), go to the Outlook directory where you found the relevant PST files, find the ones with current dates, and simply COPY them to the new directory. (Caution: you cannot do this while Outlook -- or any of the other programs that link to Outlook, such as Synchronization programs -- is running.)
Once you have done this the first time, then on following occasions you will be prompted to ask if you want to "Overwrite" or "Save both." Click on "Save both" (except as noted below), and the new copy will have a number added to the name to distinguish it from other versions.
The files will be HUGE (3,000,000 KB or more), so you may wish to start this process when you are on your way out to lunch, as it will take a few minutes.
But it will be worth it the next time you open Outlook and find that your Rules are gone or your Notes or Tasks files have disappeared.
One further caution: Do be sure that you don't get bogged down by saving a new iteration every time. After you have 2 or 3 of these "backup" files, you should begin to overwrite them (oldest one first, of course).