As I see it, academic discipline is a non-negotiable component in the classroom community. In my case, I expect students to put care and detail into their work. Refining a skill, including a mental skill (like mental maths), requires repetition--often in the form of homework. Homework puts the necessary distance between a newly learned skill and the occasion to practice it. This enhances memory consolidation, and is therefore an essential part of learning.
Generally, students in my classes can expect soft deadlines and hard deadlines for in-school work or homework. I do not see much value in giving overly restrictive deadlines.
However, assigned work must be done. Students who struggle with this are given help, particularly if a student is on a formal development plan.
Finishing a project with great care and attention to detail is a moment of great pride for every student.