The wise behavior in deflation stage is to hoard as much as you can. But it kills the economy.
Economic deflation mean that people are creating so much goods, that it effectively outstrip the demand. The price of computers has been deflating for a while, but it means bigger markets over time. People don't buy computers every year, but it become more attractive to do so every year.
Hoarding will means that you keep hoarding until you see an attractive price and buy. Effectively, hoarding is determined by your time preference. If you hoard more, you could get more at a later date, but then you won't buy anything to satisfy your needs, for now.
An extreme economic deflation will only mean our time preference will stretch, but it does not mean that our time preference can be stretch to infinity. We need food and we will buy food.