dtran1119I know the rule that we're supposed to hyphenate compound adjectives when they appear before a noun and not after a noun.
For example:
"My parents want me to attend a well-known university."
"The school I attend is well known."
Adverb-adjective compounds, as you have here, are often not hyphenated, even when they precede a noun. For example: "clearly defined rule", not "clearly-defined rule".
I've never really thought about it too much before, but off the top of my head it seems that shorter adverbs, especially those not ending "-ly", are more likely to be hyphenated in combination. For example, I think I would use a hyphen in "often-quoted passage" but I definitely wouldn't in "frequently quoted passage". "Well" is normally hyphenated in compounds peceding the noun, as in your example.
I would always use a hyphen when there is otherwise a risk of ambiguity or misassociation. For example, "fast-talking politician", not "fast talking politician".
dtran1119 Which one is correct?
1) "We should have school year-round."
2) "We should have school year round."
In this case I would definitely use a hyphen. Otherwise there is a real risk of "school year" being read as one unit. However, in "We should leave the building perfectly intact" I would not use a hyphen.
A good rule of thumb in cases of doubt: if the sentence is significantly easier to parse with a hyphen, then use one.