I attended a parents' evening recently, and was shocked by the amount of work (and homework) that doesn't seem to be marked. When I brought it to the attention of the teacher, she said that it was just to practice, and that she didn't have the time in her day to mark all of the work that was being done.
However, what if the children are getting things wrong? How are they going to find this out to improve on in the future if the work is never marked? I know that teachers are under a lot of pressure, but our children work hard on the tasks that are sent home with them, and I think it would be nice if they were then given some feedback on the work that they had done, including notes on things that they could improve in the future.