When it comes to expressing the idea that something is enough or satisfactory, there are several synonyms for the phrase "are sufficient". Some of these include "are adequate", "are satisfactory", "meet the requirements", "meet the demands", "are suitable", and "are appropriate". Other options include "are enough", "are ample", "are plentiful", "are abundant", and "are plentiful". Whichever word or phrase is used to convey this sentiment, the overarching idea remains the same: the amount or level being discussed is enough to meet the needs or expectations at hand, and there is no need for further adjustment or modification.