In May, the World Health Organization reported that globally, life expectancy increased by five years between 2000 and 2015.

Each decade since the 1950s, the number of people ages 100 and older has more than doubled.

In 1950, the average life expectancy in the United States was 68.2 years. By 2015, it had risen nearly 11.5 years to 79.68. Depending upon one’s birth year, however, the U.S. Social Security Administration’s full retirement age is between 65 and 67.

That’s too early; it’s time to think in terms of a multi-phase life replacing the “old” three-phase model — education, work and retirement. So said Avivah Wittenberg-Cox, founder of the Chautauqua and European Professional Women’s Networks, Harvard Business Review contributor, best-selling business book author and one of the world’s top gender experts and leadership coaches.

She is the CEO and managing partner of 20-first, a gender and diversity consultancy based in London, England, that advises Fortune 500 companies. Its mission is to build balanced businesses and develop gender bilingual leaders.

At 1 p.m. Monday at the Chautauqua Women’s Club House, Wittenberg-Cox will give a talk titled “Rethinking Self, Work and Love for a 100-year Life.” It will, in part, be a follow-up to her presentation last July, during which she applied “late love” lessons to the workplace.

Wittenberg-Cox just finished writing the book she began researching in 2014, which includes information from interviews with Chautauqua couples — Late Love: Can We Become Masterful at Love in the Second Half of Life?

A self-described “serial entrepreneur of sorts,” Wittenberg-Cox has shifted her focus to managing professional and personal transitions in an era of the 100-year life.

She said her most recent publication, Four Phases of Women’s Careers, encourages employers to “flexibilize.”

Working from ages 20–25 to 60–65 has created an upper-out, linear career path that does not work particularly well for women who would like to have a different career cycle and greater flexibility, especially in during their 30s. Wittenberg-Cox said that is also true for men, who increasingly want to be fathers and take parental leave.

She also said career focus has been on the first half of life — in one’s 20s, 30s and 40s.

“Now we have to throw resources at the second half, post 50s. People will have to reinvent themselves, their work and their relationships,” Wittenberg-Cox said. “It is unlikely that there will be one pattern; we’ll have multiple patterns that change regularly.”

Wittenberg-Cox has also been delving into other complex queries: How will love and work adapt to much longer lives? Will people have multiple lives, careers and partners? And can we become better at managing the transitions between them?

“How do we cope?” she said. “What does it take to be successful on this long marathon ride?”

People used to plan for their 70s and 80s. Will they have sufficient money, plans and education for a 100-year life?

Further, how can places and spaces be designed to encourage “intergenerationality,” including “intentional intergenerationality beyond the family”?

After her talk, Wittenberg-Cox will offer an optional workshop from 2:30 to 4:30 p.m. in the dining room of the CWC House for up to 12 people with a fee of $20 per person. With her guidance, participants will focus on their life phases and what’s next with respect to their self, work and love.

“Change can be expected or unexpected,” Wittenberg-Cox said. “You can want to change or be hit by it due to the loss of your job or spouse, or through dislocation.”

Resilience, self-knowledge, transformation skills and time are integral to adjusting to “the new,” she said.

Even so, change is tough; it’s easy to fall back into old, unconscious patterns and repeat what we did before.

According to Wittenberg-Cox, transitions take more time than people think they will.

“On average, it takes about three years for any mid-life shift,” she said. “You need to make sure you have the necessary support, systems and network.”

People think they’ll get help from friends and colleagues, she said. Instead, they tend to get help via the “power of weak ties” — from people they know the least.

“The people you know best are the most invested in who you are and they don’t necessarily want to see you move on,” Wittenberg-Cox said.

Although it’s the opposite of what people expect, the strongest predictors of success are one’s diversity of existing networks and new networks.

“One hundred years is an unbelievably exciting invitation to have multiple lives and selves if we embrace it,” Wittenberg-Cox said. “Or, it could be under financed repetitions.”