Redundancy is a common error in writing. Redundancy is saying the same thing twice, as in the phrases repeat again and cooperate together. Eliminating redundancies can greatly sharpen your writing. Here are some examples of sentences with redundant phrases and revisions.

Redundant: Before setting off on your camping trip, be sure you have the important essentials: food, water, and shelter.
Revised: Before setting off on your camping trip, be sure you have the essentials: food, water, and shelter.

Redundant: The dog ran away on Thursday but came back again on Saturday.
Revised: The dog ran away on Thursday but came back on Saturday.

Other redundant phrases:

• Triangular (round, square) in shape
  
• Auto-biography of my life
  
• The future to come
  
• The final conclusion