Analogy with Investment

If you want to invest in a company, you can buy shares. You make the decision based on your knowledge of the market, the company, the risk you run, and speculation about the future. Your money is tied up. If it turns out as you predicted, you can gain a lot. If it doesn't, you lose money. That's the risk you take.

Sometimes you can buy options. These enable you to buy or sell stock in the future at a price that is agreed to now. You invest very little, but you buy the right to wait to make your decision. If the value of the stocks rises, you buy and make a profit. If the value of the stocks decreases, you don't buy and lose only the price of the option.

Likewise, investing in keeping your software malleable is a small investment that pays off by giving you more options. See Chapter 43, which is based on the papers presented by John Favaro (at XP2001) and Hakan Erdogmus (at XP Universe 2001), for a complete treatment of this analogy.