Yes, "upper hand" should not be hyphenated when used as a noun. It refers to having an advantage or control in a situation. However, if it were used as a compound adjective before a noun, it could be hyphenated as "upper-hand advantage."
Yes, it should be hyphenated.
Yes it should be hyphenated.
Yes it should be hyphenated.
yes check-up should be hyphenated
It should be hyphenated.
Yes it should be hyphenated.
"Field" is not hyphenated.
Yes it should be hyphenated.
Yes it should be hyphenated.
No it shouldn't be hyphenated.
Self-made should be hyphenated.
Yes, "low-to-intermediate" should be hyphenated when used as a compound modifier before a noun.