Londonone - I take your point about not wanting to work unless you got paid. I certainly wouldn't! I think paying people to do a job is an excellent way to incentivise them. But I think being paid to do work is different from giving rewards to kids for doing "normal kids stuff", like tidying up, doing homework, practising sport or music, keeping your mouth shut while eating etc. The principle still stands that if you have been "paid" to do something, and then the payment is removed, then most people are even less likely to do that thing than before. I think most people who use reward charts aren't aware of this typical response. They think that a reward chart will motivate their child - and it can do in the short term. The problem is what happens after the reward chart is stopped.
So slightly change my example above. Take a group of 10 year olds who are having a lovely time playing outside your window and being very loud. You want a bit of peace and quiet. You call them over and tell them you love hearing them so much that you are going to give them £2 for every 30 minutes they shout and laugh and play outside your window. They enthusiastically agree and for the next week you pay each child £2 a day for making a lot of noise. After a week, you tell them that unfortunately you don't have enough money to pay them all today and you can only give them £1 each. They grumble, but carry on whooping and shouting. When they come back the next day, you tell them that unfortunately you haven't got any money and you can't pay them any more. What do they do and feel? I imagine most 10 year olds will say sod it, I'm not making noise for free. If she wants it, she can pay for it. And then bugger off and play somewhere else out of earshot. The external reward has reduced their internal motivation to do what they were previously doing just for the sheer joy of it.
And yes, I agree. I think it's nice to live in a tidy house. My kids couldn't care less. I could pay them to tidy up, or give them stickers. This would work brilliantly while I continued to give them the rewards. But I know what would happen if and when I stopped handing over the cash,and frankly, I don't want to be buying compliance when they are teenagers. Also, I don't think their husbands or wives would thank me. Somehow, I have to find a way for them to take on the value (it's nice to live in a tidy house) as their own. This might involve lots of discussion about how it's easier to find things when everything is in the right place, praise for being organized etc. It's not a quick fix, but in the long term it's more effective than reward charts.