Assumptions on income growth, interest rate trend and rental yields are important, and when they do not materialise as planned (or hoped for), the investment goes awry.

• 因此对诸如收入增长、利率走势和租金回报等，都先得做一些假设，而一旦情况和所计划的有出入(或事与愿违)，投资的棋就走错了。