Very few kids are proactive and can go out to search for extra work by themselves. If the teacher doesn't assign homework, then they will do nothing. With only one-hour lesson per week, how much knowledge can they retain? This is why a lot kids are stagnant at low level for years without any progress, and in the end sadly quit chess forever.
If a teacher has assigned homework, almost all students will put in some effort to try. If they don't, they will feel guilty and try to tell the teacher some excuses. Anyway, if they feel guilty enough, they may begin to correct their problem and do some homework. About half of students will do homework diligently, and may do a little extra. Not accidentally, these students are usually the ones who have made biggest progress in class.
I always assign homework, in my Steps class, my Tactics Workshop, even in my self-paced online class. The time needed for homework should be at least about same as the class time. For Steps class, I normally assign 3 pages of the Workbook, 12 problems per page, i.e., 36 problems per week. (much more than average 2 to 4 problems in other coaches' classes). I suggest to do 6 problems per day, taking about 10 minutes, so total will be 60 minutes per week.