Does your child get whatever he asks for or does he have to earn it?

Kids will be kids and full of demands but as parents we have to see which demands are reasonable and which are not. I don't give my kids everything that they ask for. Instead of saying a flat NO, I tell them the reason of not giving that thing at that particular time. I tell them what's reasonable and what's not! Of course, I do encourage them with gifts if they score well (not always), if they behave well. If all the demands are met, the kids will never learn to accept NO for an answer.