Hello, I had to reinstall Mavericks last week using the Recovery System (Command-R on boot, Reinstall OS X) on a MBPr. I didn't format the drive, so OS X was installed in-place. I had no issues during the process, and all my personal files were intact. However, I can't help but have this nagging feeling that there are corrupt system files on it that would cause some issues later, or that the MBPr seems slower. Am I just being paranoid?