Otherwise, what you're teaching is that if they complain you'll take care of everything. And, children have to learn to cope with frustration if they're going to become responsible adults. On the other hand, there are times when kids are stumped, and they're wasting time and energy. If they are, praise them. But, if they're off target, let them stumble a little bit, see if they can fix it, and then help set them back on track.
Homework is very important because it reinforces and solidifies what was taught that day in school.
In class, often there's not enough time for a teacher to present new concepts more than once or twice. And, to understand new material you often have to go over it many, many times. On the other hand, homework is also useful in preparing kids for the next day's lessons so that when the teacher goes over it, they're already slightly familiar with it themselves. Kids catch on quicker that way, but also they feel more secure and comfortable, which means they may actually raise their hand and volunteer to answer questions. There are many things that educators can do to make it easier for children to develop good organizational skills.