Money constantly changing does NOT add value to the economy UNLESS what you get for that money is worth more than your other alternative uses for that money. If I pay you dig a hole and then you pay me to fill it up, we've exchanged money and created nothing. In fact we've lost because we are both out the time it took us to do that task. That's why most government spending doesn't help anything. It takes $1000 from Joe, who could have used it to produce $1100 in value, and gives $800 to Fred (the compliance cost of collecting income tax is around 20%) who can't come close to $1100 in value.