Apples disk utility will repair a wide variety of errors, but they also draws the line on some other errors and then focuses on backup and a clean start. If you have a good backup but don't care to back anything up, I would just reinstall. Booting into the recovery HD racing the drive will start with a clean slate. At that point the installation process will be an excellent test whether he hardware is failing or not. That point you can restore your backup or just using the clean install. If you don't have a backup and can't get one using Apple's tools, then it might make sense to get Disk Warrior/Drive Genius or another third-party repair tool to try to repair/recover together to run again or at least get a good backup. I think of apples disk utility warning similar to run-flat tires or an engine that can shut off one cylinder and still get you home or to the repair shop under limited power. The system used to keep running until it broke catastrophically, leaving people with no warning that they needed to back up their files when disk errors started happening at elevated rates.