A: Disk Cleanup deletes temporary files (cache, recycle bin). Registry Reviver repairs the internal database that tells Windows where your files and programs are. You need both, but Registry Reviver fixes deeper performance issues that Disk Cleanup cannot touch.
A: Once per week if you install/uninstall software frequently. Once per month for casual users. The Pro version allows you to schedule automatic scans. reviversoft registry reviver
When was the last time you cleaned your Windows Registry? A: Disk Cleanup deletes temporary files (cache, recycle bin)