yum install yum-utils

• To find duplicate package: package-cleanup --dupes, clean: package-cleanup --cleandups
  
• To find broken dependencies: package-cleanup --problems
• To find libraries not required by any other package(s): package-cleanup --leaves (CAUTION: just because a library is not REQUIRED does NOT mean it is useless - it may provide useful functionality feature(s) for other package(s)).
• To find all packages not required by any other package: package-cleanup --leaves --all (see CAUTION above)
• To find packages not originating from enabled repositories: package-cleanup --orphans