One of the challenges of investing for retirement is trying to anticipate how much you need to accumulate. That’s the case in part because you can’t predict investment returns or future tax and inflation rates—which affect everyone— or more personal things like how long you’ll live. Watch part 1 The Retirement Marathon from the series Saving for Retirement in Your Working Years with syndicated financial columnist and talk show host Steve Savant.  Content: In 1900, retirement wasn’t a hot topic. Employers didn’t offer pensions, there was no Social Security, and the average life expectancy was 50. More than a century later, everything’s changed. More than 44 million people collect retirement benefits, and that number is expected to reach 72 million by 2030. And people are living much longer: Current estimates suggest that a million or more people now in their 40s can expect to live to be 100 or more. If you’d like more direction than “save as much as you can,” you might use the rule of thumb that says you’ll ideally have savings equal to 25 times the amount you’ll need to withdraw from your accounts the first year you’re retired to supplement the Social Security and pension   Read more…