Deflation encourages hoarding, which means savings, which means capital formation. The economiy is ultimately better off when we wait to build something until there are actually enough materials, tools and labor to do it. Inflation encourages spending which depletes capital formation and therefor production and therefor wealth.
Even in a severe deflationary environment, people still spend. They have to buy food. and money is no good in the first place if you don't spend it. Computers get cheaper every year and yet somehow people still buy them rather than waiting until next year when they are an even bigger bargain.
Any amount of money is the right amount. Prices adjust.