"In a recent survey of Financial Advisors ... 25% responded that they based their approach on levels of pre-retirement spending, 22% indicated that they used a rule of thumb like the 4% Rule, 19% indicated that they used some variation of the Bucket Strategy, 16% indicated that they compared assets with future liabilities and 18% indicated some other approach. [The survey] concluded that not enough Financial Advisors were using 'math and science' to develop spending budgets for their clients and should be periodically comparing the client's assets with the client's liability ... similar to how actuaries measure the funded status of pension plans[.]"