As I have said elsewhere it is mainly ESOL students who are directly concerned about grammar.
There are different opinions about the role of grammar study in learning English. Some experts think that, as students use the language for communication, they will "pick up" the grammar of English as naturally in the same way children who grow up in an English-speaking country.
However, too often I hear students (or those who have been students) making basic grammatical mistakes. Their language, especially their written language, suffers as a result.
Therefore I believe that some instruction in grammar is important.
The question is then, "How should grammar be taught?".
I have yet to see what seems to me a perfect method. But I keep on looking!