Would you change anything about how you live today if you knew when you were going to die? For most of us the answer would certainly be ‘yes’. But to what degree?

A common concern for those approaching their second half, is confusion over just how much we should save for retirement.

According to Fidelity's latest Retiree Health Care Cost Estimate, a 65-year-old couple retiring in 2016 will need an estimated $260,000 to cover health care costs in retirement.

How long will you live? If you knew the answer, it would eliminate one of the most difficult aspects of financial and retirement planning.