(CNN) -- When it came time for Sally Jennings to retire in 1989, she didn't know what to expect.
Sally Jennings took early retirement trips to Australia but the novelty soon wore off.
"It was kind of a shock to my system," she said. "I would go out shopping in the daytime and I felt like I was playing hooky at school."
Jennings was just the third woman to earn a chemical engineering degree at the University of Kansas when she graduated in 1963. She served in the Air Force and then went on to enjoy a decades-long tenure at Texaco Chemical.
The transition from the work force to retirement is often measured in financial and career-centric terms: When is the time right? How big is the nest egg? How to spend it?
But often overlooked in that transition are emotional challenges like a change in identity and questions over self-worth and purpose, which can undermine the golden years.
The emotional balance for those approaching retirement is a "combination of excitement with underlying trepidation," said Dr. Dwight Moore, a psychologist and the president of LifeShift, a program that helps professionals prepare for retirement.
The transition has various stages, he said. The first stage, which lasts about a year, is excitement. Retirees rest, go on trips, downsize their homes or do the things they've always wanted to do.
"I went to Australia a couple of times, Japan a couple of times, I went to Europe more times than I can count," Jennings said.
After the novelty of retirement wears off, Moore said, people start asking themselves, "Now what do I do?"
"The first sense of emotion is loss, [particularly a] loss of identity," he said. "The second is a sense of fear of 'how am I going to replace the kind of affirmation that I got.'"
With the absence of affirmation professionals get from their careers and with no boss or business demanding their expertise anymore, retirees are often left searching for self-worth.
"You lose who you are. You lose the work identity and the work context," Moore said.
Retirees who adjust the best don't think of the transition as retirement because the word carries a passive and negative connotation, Moore said. "They think about it as their next career, the next stage, the next chapter in my life," he said.
John Crawford, a former vice president with American Express, said he began preparing for his retirement years in advance.
"The bigger focus was on the psychological part rather than the financial part," he said. "The financial part was what the company and I had already worked on."
"It's easy to think about trips you want to take and things like that to do, but just the shift in the everyday pattern is a big challenge," Crawford said.
It's important for retirees to use their newfound freedom doing things that match their interests, Crawford said. The problem is not necessarily finding things to do, but finding things that are satisfying, he said.
"There was a tendency to think like school's out," Crawford said.
Reminding himself that not every day was Saturday, Crawford took Spanish classes, headed up a church committee, joined a book club, studied history and began leading his grandson's Cub Scout troop.
"I can contribute the things I learned in the business world to things I do here," he said. "Now rather than make checklists for work, it's things I want to accomplish today, tomorrow and the next day, even into next year."
Jennings also tapped into her interests, taking up photography, literature and starting her own blog. She adjusted to her new pace.
"I enjoyed my freedom," she said. "I enjoyed being out of the corporate life."
Another aspect of retirement often overlooked is the amount of time retirees share with a spouse or partner. "The cute quote is, 'I married you for better or worse, but not for lunch,'" Moore said.
Morag Orr-Stevens retired at 47 to be with her husband and focus on her painting. The adjustment was difficult because her husband had retired first and wasn't used to having her around.
"He had to adjust to me because he had been home all day alone, doing his thing and then I was there all day," she said. "He had me all day telling him what to do."
Crawford and his wife make sure to spend time apart each evening. She goes upstairs to read and watch television; he goes downstairs to work in his office. "Then we come up at about 10 o'clock and meet in the middle," he said.
Despite the adjustments and difficulties, retirement is the payoff he had worked years for, Crawford said. "What I really worked for through the years was the independence of choosing what I want to do and part of it was choosing not to work," he said.
"It's kind of like being a child. You can go and color the book any way you want to right now." E-mail to a friend