Imagine I need a car and I hear there is a 30% off sale in January. Yes, I'll wait. Im considering the lost marginal value to me (keeping my shitty car in December) vs marginal gain (saving 30%). That's what deflation feels like.
But as far as I can see, you wouldn't have bought the car without deflation (or a sale, as it were), because you couldn't afford it. So in this case it causes you to spend money that you wouldn't have spent otherwise.
> In a predictably deflationary environment, you maximize your economy by spending your money "later".
Which, in fact, is better said as:
> In a predictably deflationary environment, you maximize your economy by not spending money.
And that leads us to the obvious fact that saving up money in order to not spend them is absolutely pointless.