On the Catalog window | Course Attributes tab | Repeatable group box, there are two fields labeled Times May Be Taken. One is for the course, and the other is for its lab. The Times May Be Taken columns become active when you select the Course Repeatable and Lab Repeatable checkboxes.
Use the Times May Be Taken columns to limit the number of times the student can register for the course.
If a student attempts to exceed the limit, they will not be able to register for the course online. In J1 Desktop, a user with rights to override repeat errors could register the student after receiving a warning message.