Oh, dude, technically speaking, "world champion" should be hyphenated when used as a compound adjective before a noun, like "world-champion swimmer." But if it's after the noun, like "swimmer is world champion," then no hyphen is needed. So, like, it really depends on where you're placing it in the sentence.
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.