Good for you, damn glad to see somebody with an active interest in their kids learning.
Sadly, in many cases your/mine/our input and oversight isnt wanted. Indeed the trend seems to be that we are to be excluded completely. We might get involved and interfere with the satus quo.
I agree in the main with concern. Samson child is in a different place than most high school students, one that's right for him and luckily he has the parents that will make the system work for him.
The idea of parents being on top of what their kids are doing and what the school is teaching,

. With that said, there are markers of where parents day-to-day interaction with school and assignments should be intense and then lay off. Of course, some kids need much more help than others, some are born to succeed in school.
K-2 School and parent interaction should be ongoing. Good practices would indicate at least a weekly newsletter, even daily if online postings are possible. Spelling words, pretests, tests should be on same days. Every day there should be math and reading work for home. Daily and weekly folders should contain both examples of work before and after grading. Homework should be practice only-no new material and take no longer than 15-20 minutes for average child.
3rd Homework time would increase to 20-30 minutes for average child. Again there should be nightly math and reading. Assignment notebooks should begin, with both parent and teacher signatures required at least until there are 3 weeks of perfect entries regarding assignments and materials home. Same spelling requirements regarding pretests, etc. Homework still should be 'practice only, not applying concepts.'
4th Probably the most traumatic year for kids and parents. Homework jumps to 30-45 minutes on average, sometimes an hour. Still math, reading, spelling. Add in daily math fact tests, timed on top. Science and social studies homework becomes more frequent, often entailing written responses. Vocabulary related to subject matter jargon becomes much more difficult and part of homework. Heavy emphasis on projects and individual responsibilities. Assignment notebooks should no longer be an issue, if so, the parents and teacher need to make clear to student that this is something that must be mastered.
5th Pretty static from 4th grade. Since the kids already have done the 4th grade, homework time might actually decrease. Problem for most-hormones are going nuts!
6-8th Middle school years in most locales. Homework times differ greatly depending on student, different teachers, and curriculum. May vary from little or occasionally none to an hour or more. Tests in language arts, math, science tend towards objective grading. Test and assignments in reading, social studies, and science tend more so towards subjective and written work. Often involving 2-4 week projects, the student must develop skills on breaking down work into chunks. If the teacher is just saying that a project is due in 4 weeks, without breaking it into steps-GET IN THERE AND DEMAND WHAT IS EXPECTED AND WHEN. These are skills that a person needs in high school and beyond, allocating time is very difficult for most kids, they cannot do it on their own.
Most 6th graders need literally a step-by-step model, with examples.
7th graders need the model with anything new, using examples.
8th graders should be able to chunk the work on their own. They shouldn't require grading for bibliographies. They should know and avoid plagiarism. There should be time alloted though for students to one-on-one with instructor on where they have questions or need suggestions.
In all cases a rubric, which spells out each part of the project with criteria should be provided with the lesson assigned. The kid should know from day 1 what an 'A, B, C, D' project looks like. The objectives of the project should also be given on the assignment. This means: When finished, this is what the project demonstrates I have mastered.
Some 6th graders are good to go when they get the assignment, rubric, and due date. Some 8th graders aren't. The teacher should know the older kids that aren't ready and be in contact with the parents.
Having taught middle school for more than a decade, the average 6th grader needs lots of feedback from teacher, each step of the way. 7th graders are mostly on task, though they need help at staying on schedule. The 8th graders that have problems are few, usually they either hate school because of social or home problems or really having trouble keeping up. If the child is having major issues with completing assignments serious conferences are indicated. High school is going to be very difficult if things do not change.
Most public middle schools have instituted blocs for the kids-often overlapping curriculum with appropriate time alloted. Social studies or science often team up with reading/language arts. Instead of 2 periods of 50 minutes, there is a bloc of 110 minutes. Assigned project may be Native Americans with social studies giving background on a novel. The content of project graded by social studies teacher, the style graded by language arts teacher. Often the same teachers will 'remain' with the same group of kids throughout middle school-a great idea for most! However, not so good if personality problems with your child and one of the teachers.
In high school, little team teaching. Little or no repetition of teachers through 9-12th grades. In big high schools, I went to one of 4k+, the likelihood of the teacher really knowing the average student? Not so good. They are grading their work, they have little clue if it's their 'best' or 'done in the morning' work.
Truth to tell, the best thing that parents can do for their kids, if they want them to be successful:
Early years:
make sure they know where they are to work at home, until high school my kids knew that was the kitchen table, so I could monitor. From preschool, let them know where their backpack goes. Tell them where to put notes, letters, etc., as soon as they come home-this avoids the need for safety pins. By 3rd grade, make it clear that if they fail to give notes, etc., there are consequences. Follow through.
Be clear on the order to do things. For my kids it was come home and put backpack on kitchen floor. Change clothes. Eat snack. Outside for about 1/2 hour. Homework. Everything back in backpack, including anything requiring parent signatures, $$, etc. Leave book bag on hook by door-Basically you want them to trip/stumble over them in the morning-then they won't be forgotten. If time before dinner, outside. If not, finish homework after dinner. 1/2 hour tv or computer. Shower, story (when little), bed.
1-3 grade bedtime was 8 pm.
4-5 8:30pm
6-8 10 pm
High school-good luck with that. BTW, there were nights in hs where my kids were still working on homework until 1:30 am. All of them were in at least 2 extra curricular activities and 2 had multiple honors/AP courses.
Just like at school, home involvement should evolve, with the child becoming more independent over time.