There are so many rules of thumb to guide one’s retirement. Here’s another. You will need 70 to 80 percent of your pre-retirement income to live comfortably once you depart the workforce. In other words, your income won’t need to be as high in retirement as it was when you were working. That’s because once you retire, your expenses will presumably fall. But as indicated by USNews, many financial experts advise against adhering to such advice. Anirban has more.