When should I store my data in a reference ... versus an array

In general consider using a reference when you plan to do 1 or more of these:

• Passing your array to/from subroutines
• Combining your array into a larger structure (see perldsc)
• Using it as an object (unlikely, but not unheard of)
• Having multiple references to the same data (obviously)

See also the References tutorials subsection for other good info.