The best software for maintaining any Mac, is any of a number of backup software titles*:
http://www.macmaps.com/backup.html
Utilities which repair your Mac are great like Disk Warrior, however, if you aren't backed up, they can be as dangerous to your data integrity as accidently deleting a file, if not more so. The reason is that hard drives can fail at ANY time. That's right, ANY time. And practically no warning will come when that happens. So backup your data first, then worry about maintaining your Mac as optimized as it can be.
- * Links to my pages may give me compensation.