How important is it to use a comma before a coordinating conjunction in writing these days?
For example, “Every morning, I wake up at 6:00 am and then I make a cup of coffee.”
As a writing teacher for international students, I see this kind of sentence all the time. I know it is technically correct to use a comma before a coordinating conjunction, but I have found that so many Americans omit this comma that it has become extremely commonplace even among native English speakers. Is it socially acceptable in writing to omit the comma? How serious is it to mandate that my international include this comma?