Yes, "year to date" should be hyphenated when used as a compound adjective before a noun, as in "year-to-date performance." However, when it appears after the noun, such as "the performance year to date," no hyphens are needed. Always consider the context to determine the correct usage.
Hyphens not needed
Yes it should.
Yes, "year to date" is typically written without hyphens when used in a sentence. However, when used as a compound adjective before a noun, it is often hyphenated as "year-to-date." For example, you would say "The year-to-date figures show an increase."
no hyphens - 57 years old is what you are.
Yes it should be hyphenated.
Yes, you should use hyphens in "eleven-year-old" when it functions as a compound adjective before a noun. For example, you would say "an eleven-year-old child." However, when using it as a predicate adjective after a verb, you do not need hyphens: "The child is eleven years old."
If you're using the phrase as an adjective (example "This easy-to-use remote is great!") then it will definitely need the hyphens. Otherwise, the hyphens are incorrect.
Yes, there should be hyphens in "thirty-year-old" when used as a compound adjective before a noun. The correct phrasing would be "a thirty-year-old civil war." The hyphens help clarify that "thirty-year-old" is a single descriptor for the civil war.
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.
It should be "up-to-date". You will see it in many instances written "up to date" without the hyphens, where each word becomes a separate and different part of speech, which may be confusing. (Hyphens are grossly and woefully under-used in adjectives.)
Most people would spell it sixteen-year-old child. But over the last 20 years, people are ignoring the hyphens.
Yes, "year after year" should be hyphenated when used as a compound adjective before a noun (e.g., year-after-year performance). However, it is not hyphenated when used as an adverbial phrase (e.g., they met year after year).