Who are the Super Savers Among Millennials and Gen Xers?

"They were willing to do less … but they're not miserable, still willing watching "Seinfeld" on Netflix, "Mr. Robot" on Amazon Prime, and still traveling, still eating out," says Jerry Patterson, senior vice president, Retirement & Income Solutions at Principal. "It's just that they're balancing better."

Seventy-one percent of super savers reported they starting saving for retirement when they were in their 20s, which may reflect their lack of confidence in Social Security. Just 34% of super savers and 37% of pre-super savers said they include Social Security benefits in their financial planning, suggesting that well more than half don't have much confidence of collecting benefits when they retire. But 43% of both groups said they were confident about saving for retirement.

One reason for that confidence could be the high percentage of both groups who report working with a financial advisor — 41% of super savers and 42% of pre-super savers. Another 20% or so of both groups currently don't work with an advisor but plan to in the future.

Despite those connections with a financial advisor, only 2% of both groups said a financial advisor influenced their savings habits; 34% said a parent did.

Although roughly one-third of both groups plan to retire between 60 and 64 and close to 40% plan to retire between 65 and 70, one-quarter of super savers and 18% of pre-super savers expect to retire between 50 and 59.

Despite their savings behavior, a whopping 81% of both groups said they learned little to nothing about personal finance in school, and 98% believed they should have received that education before graduating from high school.