How many times have you gotten half way down the page typing and something has happened that made you lose the whole thing? It has happened to me many times (unfortunately). If you are using Microsoft Word it does have a back up and recovery feature, but it isn’t foolproof, you still can lose a lot of work.
There are many other programs that may be used on a daily basis that don’t have this recovery feature. One rule of thumb is to save right away and then save every 5 or so minutes. I suggest every time you are done with another paragraph or a big change click that save button or press CTRL + S.