I’ve read students’ essays that contained nary a comma. On the other hand, I’ve read essays that had a comma inserted after about every third word. The comma, one of the most commonly used — and useful — punctuation marks, doesn’t have that many uses. So learn them.
Note the difference that a comma would make here (from a student’s narrative essay about observing kindergarteners at lunch and in the classroom): “When the students finished eating the teacher escorted them back to class.” Yikes! The kids ate “Teach.” My response: “Did she taste good?” A comma after "finished" is essential!
Another Egregious Example, compliments of a student writing about a wayward bug: “My dad killed the cockroach and my mom
was happy.” Oh-oh. Why was she so happy if her husband had killed her? Inserting a comma after “cockroach” would have solved the problem. (Should I even mention that the correct transition, in this case, would be “so,” not “and” — to show cause and effect?)
How about this Egregious Example? “This four-bedroom, three-bathroom home offers a sparkling pool and spa, a tropical tiki hut that’s fully equipped for entertaining and an incredibly scenic location.” A comma after "entertaining" would improve readability; otherwise, it reads as if the tiki hut is "equipped for entertaining and an incredibly scenice location."