Lockers also help students to look their best. Many students hang a small mirror inside their locker. This way, they can comb their hair or put on makeup in between classes.


Is the bolded in in the above optional? If not, what meanings does the above lose with "in?" Thanks.
It is optional. 'In between' is less formal.
AngliholicIs the bolded in in the above optional
Yeah I think it's optional.