Local History fills the void between version control systems and doing nothing at all. Whenever you save your project or build your project (which automatically saves it), the IDE takes a "snapshot" of all your source files. The Local History feature enables you to look back in time and compare the current version of a file with its previous incarnations, each with a time and date stamp. The built-in diff utility makes it possible to add or remove differing parts or even to revert the entire file to a previous state. By default these snapshots are saved for 7 days, but you can easily extend that to 999,999 days if you wish.
Local History in MPLAB® X IDE