Social Security benefits are one of the great unknowns when it comes to retirement planning. Baby Boomers don't have much to worry about since the Social Security trust fund isn't expected to run out of funds until sometime after 2027, but what about the younger generations? Should they be taking Social Security benefits into account when they formulate their retirement savings goals?

Even if Generation X and younger don't have access to full benefits, there will be some money left in the system, even if it means individuals receive 75 percent of their current expected benefits instead of 100 percent, said Robert Henderson, president of Lansdowne Wealth Management, LLC in Mystic, Conn.

"For younger people, if somebody is 20 years or more away from retirement, it's not that I don't think Social Security is going to be there because I do, but it is so difficult to predict what the amounts are going to be," he said. "A lot of things can change with Congress and our economy over 20-plus years. In addition, a lot of things can change with individuals' circumstances, like how much they work, how much they earn and the types of jobs they have."