You say it yourself: Saving to use that money later. Which is an issue as economic measurements are based on what the economy is like at the present moment. If a large amount of people's capital is sitting dormant in bank accounts it can't flow through the economy. This used not to be such a huge problem because banks were allowed to re-invest savings (fractional reserve lending), but this changed after 2008. The problem with Austerity is that it doesn't encourage people to spend. It damages consumer sentiment, which makes people more inclined to save for a rainy day, which has a knock on effect in the shops and restaurants, and ultimately the tax take that these businesses bring in. Of course, if all people were rational, and self-interested this may not be a problem, but this is counterbalanced by Keyne's "Animal Spirits" or the irrational behaviour of people en mass. I'm not saying that either style of economics is 100% right or wrong, but that it is a delicate balancing act between the two.