InDesign guards your data against unexpected power or system failures using an automatic recovery feature. Automatically recovered data exists in a temporary file that is separate from the original document file on disk. Under normal circumstances you don’t need to think about automatically recovered data, because any document updates stored in the automatic recovery file are automatically added to the original document file when you choose the Save or Save As command or exit from InDesign normally. Automatically recovered data is important only if you’re unable to save successfully before an unexpected power or system failure.
Even though these features exist, you should save your files often and create backup files in case of unexpected power or system failures.