Yes, "year-end" should have a hyphen when used as an adjective, such as in "year-end report." However, when used as a noun, it can be written as "year end" without a hyphen. The hyphen helps clarify that the two words function together as a single descriptive term.
Yes
No it doesn't require to be hyphenated.
Yes it should be hyphenated.
Four-year should be hyphenated but not institution.
It Is A Special Hyphen
Non-breaking hyphen
Nonbreaking Hyphen
You should use a hyphen to represent years with more than two digits that end in a number other than zero, such as twenty-seven and one hundred and thirty-three. The hyphen is only used between the last two digits.
If you're using the phrase as an adjective (example "I hate the end-of-the-year audit!") then it will definitely need the hyphens. Otherwise, the hyphens are incorrect.
No, a hyphen is not needed.
Yes, the hyphen goes in the word "dead-end" because the two words together have a different meaning than separately.
Tumblr URLs can't start or end with a hyphen.