The age-old, burning question uppermost in every mind....
Let me remedy that for you:
If you use a compound modifier as an adjectival predicate (AFTER the noun phrase, as in "Sam is anal retentive") then you do not hyphenate.
However, if you use as an attributive compound (modifiers prior to the noun phrase), it is hyphenated (as in "Sam is an anal-retentive editor")
You're welcome