How important is System Maintenance?

Research a scholarly paper or professional video on “System Implementation and Maintenance” and reflect on only one of the following topics:
“Issues”: What is the common issue during System Implementation?
“Types”: What types of System Maintenance are used in industry?
“Importance”: How important is System Maintenance?
“BPR”: How does System Maintenance correspond with Business Process Reengineering or Redesign? 
NOTE:
You must copy and paste the topic (“Issues” or “Types” or “Importance” or “BPR”) at the start of your paper to provide a context for your answer.
This paper must be between 250-300 words on what caught your eye and reflect on what you read.