Today’s advice is to backup your site, backup your project files, backup everything you care about. I had awfully bad experience with this, every once in a while Photoshop decides to be a d*ck, refusing to open my PSD files.
It’s either bad luck or bad bug, but it hurts when you have to start all over again. I won’t talk about all the Photoshop bugs i had to deal with. If you work on Photoshop CS6 you shouldn’t worry much, because they have added file recovering system. But still a lot of people are working on older versions, so my advice to them is to start backing up their work on a cloud storage service. In case your computer explode or your Photoshop acts like a d*ck, you will have your files in safe.