Try reading some of the research on this subject. Obviously kids need to practice things to get good at them, but at the elementary age, they don't need to be practicing more than the 6-7 hours a day they spend in school. Of course, parents should encourage kids to pursue personal interests that inherently reinforce academic type skills -- reading whatever books interest them, building playhouses (takes quite a bit of measuring and planning), and in my case, forming little "clubs" with my little friends, which entailed writing exhaustive lists of rules, statements of purpose, initiation ceremonies, etc. I'm not suggesting that kids should come home and lounge in front of the TV or play video games 'til bedtime.
I did NO homework, even through high school at a tough prep school, and it didn't hurt me a bit. Sure, I got exceptionally crappy grades, but all the things I learned in the many hours I devoted to things I was really interested in kept my brain developing nicely. I had one of the very lowest GPAs in my high school class, but the highest SAT scores in the class. I was in the bottom 10% of my college class GPA, but had LSAT scores in the top 10%. I'm now quite successful as a banker, and making plenty of money. And I'm taking science courses at night for fun (the serious kind, for science majors, pre-meds, etc.), and getting all A's -- because I want to, not because somebody's telling me I can't go play with my friends or read the book I want to read, until I've done my "homework" for the zillionth time.
Schools should not be allowed to program nearly all of kids' waking hours, shoving out other activities that the children and their parents choose. And if schools wouldn't waste half the school day on nonsense, and on long explanations of the projects that are being assigned to devour kids' free time, and on worthless "presentations" of these "projects", kids could learn plenty during the school day. I've even heard of 5th graders being expected to give PowerPoint presentations and 4th graders being required to produce a "magazine" complete with pictures, index, etc. No wonder they can't multiply or spell or think. If little kids get the idea with their little friends that they want to make a play magazine, that's great. But it's a game, not real work.
My 2nd graders learned how to make Power Point Presentations.
They actually like it, and one of them makes them for fun at home.
I think the homework should be to study for tests. The kids and parents should know when the tests are and what the material is. If the kids need to work to do well on those tests, then fine. If the kids don't need to work, then they get to play more. Fine with me also.
The parents and the kids can figure out the best way to prepare for a test.
I'm talking about elementary school. High School is different.