Excel Has Stopped Working

You are not the only one. I get this crash from time to time. I have no idea what causes excel to suddenly stops and get this error message, but my poor guesses are the following.
I notice this error when I work with a share book, i.e. the book is saved on the server and could be accessed by many users.
I have also notice this when the PC has not got enough RAM and hard drive.
When excels restarts it gives you the option to retrieve the old file, but some of the work might have been lost. I think this option is removed in 2013.
I do not see any solution except to save your work every 5-10 minutes or use the auto save option where excel save it auto . The auto option removes the risk of forgetting to save the file.