No, "sign up" is not hyphenated when used as a verb (e.g., "Please sign up for the newsletter"). However, when used as a noun or adjective, it can be hyphenated as "sign-up" (e.g., "The sign-up sheet is on the table").
No, "sign off" is not hyphenated when used as a verb. However, it can be hyphenated when used as a noun (e.g., "She gave her sign-off on the project").
yes check-up should be hyphenated
"Fired up" is one of those phrases that is hyphenated when it is used as a modifier preceding whatever it is modifying, but not hyphenated when it is used as a predicate adjective. For example, if you say "Everyone was fired up about the new project", "fired up" is a predicate adjective and not hyphenated. However, if you refer to someone's "fired-up speech", "fired-up" is a modifier that precedes "speech" and is therefore hyphenated. Using "fired up" as a predicate adjective is more common.
followup This word spelled as is does not come up on Answers.com spell check. Followup is not hyphenated.
does write up need a hyphen
stand-up guy
yes
The term "check-up" is hyphenated when used as a noun, such as in "I have a check-up scheduled." However, when used as a verb, it is written as "check up," as in "I need to check up on my health."
Can someone answer I would like to know too.... Ie Mary-Jane or Jai-Lynn
Yes, "to-date" is hyphenated when used as an adjective before a noun (e.g. up-to-date information) or as an adverb following a verb (e.g. the report is up to date).
It is not hyphenated.
The term mix-up (noun) is usually hyphenated.