The Jet Report Doctor - Proper filter technique with summary functions

The Story:
A customer sent me a report saying, "this report takes forever long to run and I keep getting rows with 0's in them."

Usually when it comes to summary reports (using NL("Sum") and Summary Lists or Grouping Reports), the culprit behind poor report performance is inconsistent filters.  To set my client straight, I laid down the following ground rules:

• Always put filter criteria in the TOP LEFT
  
• Each NL() summary function (Rows, Columns, Sum, Count, CountUnique) must have the same number of filter criteria
  
• Never filter on the same field twice
  
• If a filter only affects a region of the report, move the filter to that region

Good luck!