Hi Rivendell Gaming,
Firstly, I am not associated with Laminar Research (LR). I am just a flight simmer.
If you have loaded X-plane 10 correctly and as recommended by LR then it should be on you desktop. I have loaded it to a specific dedicated drive. I find it works without any problems. I also have another dedicated drive as my "hangar" drive whereby I have a complete copy of X-plane 10 as my backup.
It is a stand-alone program that does not insert any of its files into other software eg Windows operating files like Microsoft Office does. This means if you copy the x-plane directory you will copy it in full. The comparison is when you copy a single file from one location to another whether it be onto a portable device (USB stick) or another location on your main hard drive.
There are others in this forum who have asked the question "How many copies of X-plane can I run on my computer"? The answers given is that you can run as many copies as you like. To do so, purchase your original copy/version and then copy to wherever you wish. All versions should be the same.
As Mattrauch has indicated below he has backed up to a USB Flash drive. The drive would have to be of sufficient capacity to copy X-plane in total. As X-plane 10 is approximately 24Gb in its total expanded state without any add-ons or plugins. His drive would have to be at least 32Gb. If you used an external system eg USB stick and backed up regularly ie copied, you could store it in a "safe " location, provided you can remember where you stored it, for later use if needed.
I also understand that X-plane 11 will do exactly the same when loaded. It will not overwrite any X-plane 10 files and will not load some files into other unknown areas on your PC. This means that when X-plane 11 is officially released you can have 2 versions of X-Plane on your computer, providing a copy of both packages for use without one package impacting on the other.
The following Youtube video link from Wycliffe Barrett may also be of interest as he explains in his comment about "reinstalling" X-plane that he has several versions of X-Plane on his PC. This may provide an alternative answer to your original question. The link is as follows https://www.youtube.com/watch?v=l9wubukUlxI
Hope this helps.
Glenn