It would depend upon the context. Enough = adverb 1. to the required degree or extent (used after an adjective, adverb, or verb). "before he was old enough to shave" (before he was sufficient enough to shave = nonsense in this sentence) Sufficient = the same = a pronoun or adjective, but with the meaning of meeting a need/requirement. "after finishing the meal = was sufficiently full" "after finishing the meal he had had enough" "after finishing the meal he was enough filled" = wrong and nonsense. "after finishing the meal he was full enough" = above sentence corrected so there are occasionally times when there is a need to use one word rather than the other. if talking about meting a current need then you can use either, but enough is more colloquial and sufficient is more for formal speaking and/or writing. If talking about fulfilling something to a degree then use enough. sufficient is used more in legal documents etc.

Thanks guys

"30 minutes is enough." OK "30 minutes is sufficient." OK "learning grammar is enough." OK "learning grammar is sufficient." WRONG Very few words in the english language mean exactly the same thing in all contexts and situations, English words were borrowed from other languages over a long time to add fine detail and shading.

They are basically the same. To me, when using "sufficient," you sound a bit more posh, more sophisticated, while "enough" is more everyday, common language. You also hear "enough" being used much more then "sufficient," at least in my experience with the english language. With your two examples, i would use "enough".

They mean exactly the same thing! The feeling is a bit different though— “Enough” is a German origin word, and “sufficient” is from Latin. In English, words that come from German feel comfortable and easy. Words that come from Latin usually feel like school words or legal words.