(FORTUNE Magazine) - Nothing jump-starts the take-stock-of-life brain waves quite like a college reunion--particularly one of the milestone variety. I should know. I just returned from my 25th at my alma mater, Bowdoin College, up in the rainy state of Maine. I must confess to being somewhat of a reunion junkie. I show up faithfully every five years, even though I always leave with my head ringing like a just-struck tuning fork. This has less to do with the quantity of alcohol consumed than it does with the inevitable comparing and contrasting with classmates.

I was particularly interested to find out how my old pals were faring this time around, given that the 25th reunion is sometimes looked upon as a halfway point in the productive portion of your life. What plans were being hatched for retirement? Did anyone wonder what the second half held in store? My deep-seated musings were immediately brought to the surface on Saturday morning. I had been tapped to be co-marshal of the convocation procession along with my pal Mary Kate. She was chosen for her grace, charm, and dedicated service to the college. They must have also wanted someone with a suboptimal GPA whose last name begins with S.

During the ceremony we were seated directly adjacent to the assembled class of 1956 (celebrating their 50th reunion, of course). And as I scrutinized the contented-looking contingent of seventysomethings, I realized that soon enough we would become them. If we were lucky. Presently, the chair of the alumni fundraising group announced how much money each reunion class had raised over the previous year. "Class of 1981: $461,355," she said. "Class of 1956: $15 million!" Mary Kate and I looked at each other with mouths agape. Halfway in, we apparently still have some catching up to do.

On the other hand, even after factoring in reunion bias (since successful folks are more likely to show up), it appears that most of my classmates are thriving--although some interesting lessons have been learned along the way. We have some slam-dunkers like Mac, now said to be one of the highest-paid people on Wall Street. Then there's DD, a successful investment banker who told me how he had followed his plan to bust his hump logging 70-hour weeks in his 30s so he could retire early, which he did.

"But now I realize that early retirement is a myth," DD told me, "because the only people around during the day are 20 years old or 70." DD, like other friends of mine who checked out before they received their first AARP solicitation, hadn't counted on missing the camaraderie and the exchange of ideas that came with work. "It was great to take a break in midlife," says DD, "but I'm going back to work."

Then there's my pal Dave. With a few exceptions (including yours truly), one trend I noticed is how few of my classmates work for large companies anymore. But Dave is a lifer in the Big Show. He recently traded in his ID badge as an executive at one FORTUNE 500 company for another, both in the Midwest. "It's impressive to see classmates following their dream instead of just paying off their mortgage like I sometimes feel like I'm doing," says Dave.

Not that corporate America has brought him much more security. "I think about retirement, though I really don't have a time frame. But you have to figure there aren't many people over 60 in these jobs." Dave said he was doing "conventional stuff," like contributing to his 401(k)--that and saving for his three kids' education. "I see some investment bankers looking for weird ways to finance their kids' education," says Dave, who eschews the pursuit of scholarship loopholes. "But I believe an education is worth paying for. You may not see the returns right away, but down the road it's worth it." Like in 25 or 50 years. And all the years before and after that too. Talking with Dave reminds me that these signpost moments are a major deal. But not as important as the road itself.