Underdeveloped should be written as one word, not two words or hyphenated. I hope this answered your question. :)
Roller-skate, as a verb, should be hyphenated. Roller skate, as a noun, is not.
One word is fine.
Self-made should be hyphenated.
Pre construction - two words not hyphenated.
No, "fourth floor" is not hyphenated. It is written as two separate words.
It should be hyphenated when it's used as an adjective.
"Check-in" should be hyphenated when used as a noun or an adjective, such as "The check-in process was smooth." However, when used as a verb, it is typically written as two separate words: "Please check in at the front desk."
self conscious
No.
Roller-skate, as a verb, should be hyphenated. Roller skate, as a noun, is not.
No, "miles per hour" is not hyphenated. It is written as three separate words.
No, "self respect" is not a hyphenated word. It is typically written as two separate words.