A remark from a recent experience I had:
I save my model on a Dropbox folder, and it saved me.

I model an old, big house with a very long and narrow garden. When I added the garden to the plan, it made the 3D view very hard to navigate, as it is always centered on the middle of the model.
Anyway, I temporarily removed the garden to view something precisely, but I forgot and I made another change, and saved my model… The garden was lost!

I went to the Dropbox folder on the Web, it allowed me to view the (recent) history of the file, and by restoring a few versions, I found the one with the garden!

Note: perhaps using Git or similar can be useful, too, but then, you have to remember to commit the changes…