DS (Y2) does his 'homework' in his first language (not English) every day. Some of it he can do independently, some he needs help/assistance with. We rotate the subjects, because we don't have enough time to do them all the way you would do in school, so he completed a writing workbook last year (1 page a day), then did a maths workbook which he really enjoyed, and now we're doing literature (midway), after which we'll probably go back to writing again (a different level obviously). Some days DS writes emails to extended family and this also counts as practising his native tongue (so he doesn't need to do his 'homework' that day). We started to do this on a daily basis in the middle of Y1, and before that he had worksheets and activities to do, but he only did them when and if he wanted to.
1-2 days a week are reserved for his homework from school (in English). School homework is 1 book a week to read, and a task in his 'Learn by heart' workbook every other week. The book that he's got from school right now has 162 pages in it
Mostly DS does his English homework by himself, although I do help him if he wants/needs me to.
In Y1 we have also done school maths workbook which reflected what kids learn in the class. I don't think it taught DS anything new but he enjoyed doing it, and it opened up conversations about how they learn this material in school, what he likes, what he finds easy/difficult and so on. So was worthwhile but not necessarily from learning/development point of view.
DD (Reception) gets 'homework' in her first language too but can choose whether she wants to do it or not. Most days she wants to do it because that's what her brother does and she wants to be as good!
Homework from school (in English) she must do. This is currently 1 book a week for her to read, and 1 book every other week to read together (this is a book that she chooses herself, and is often well beyond her reading ability).
We spend about 20-30 minutes on the homework a day. Tasks themselves don't take this long but organising 2 children and answering all their questions along the way makes it half an hour. Also, oftentimes DD wants to also do (or at least look at!) DS's homework and vice versa!