The Martinez family sat outside on picnic tables in the Texas heat, temperatures rising above 100 degrees, and listened to the story of how some of the refugees made it to this country.

Megan Martinez, 33, studied the murals painted on the fence next to them -- portraits of people who had traveled by packed trains through South America. At various points, the shelter director explained, people would throw food on the train so the passengers could survive until the next stop.

Megan's 17-year-old stepson, Holden, was absorbed in the story told by the director of Casa Marianella in Austin, Texas. Later that evening, Holden would be cooking dinner for the families staying at the shelter. He would take special care to make the spaghetti sauce from scratch for them.

Megan describes this moment of their family vacation as life-changing.

"Seeing my kids understand the system, learning about how people come to live here because it's not safe to live in their own country, seeing the wheels in their heads turning ... as a parent, that was huge."

This was the second summer the Martinezes, who live in the St. Louis area, embraced the idea of vacationing for a good cause. As part of their annual 10-day summer vacation, each family member -- Megan, husband Chris, 41, and their three children, ages 17, 9 and 8 -- took a role in planning a different volunteer project. They drove from St. Louis to Texas and worked on six service projects during the trip. They helped sort donations at a distribution center for the Joplin School District in Missouri. In Dallas, they took down a sunflower display at Peace Community Gardens in preparation for its move to a new location. In San Antonio, they worked a Family Fun Night at the San Antonio Museum of Art. They cooked and served dinner at the refugee shelter in Austin. And they painted and assembled temporary huts for people still living in tents after this summer's tornados in Oklahoma City.

Holden said he got to practice his Spanish while talking to residents at Casa Marianella, and it changed his perspective on the sorts of problems that come up in a typical, middle-class American high school.

"It was kinda cool how they could be so positive and so happy despite all they had been through," he said.

Chris Martinez, who works as the chief development officer for Catholic Charities, and Megan, who works as the recreation director for Missouri's Veteran's Home, are naturally service-oriented people. They wanted to find ways to foster the same spirit in their children and discovered that the family vacation was an opportunity to combine relaxation and volunteering. Each family member researched organizations in advance, then sent emails to see if there were opportunities for the family to help out for a few hours during their visit.

"You can walk out after performing a project and not have to say anything," Chris said. "What they witnessed is so much more powerful than anything my wife or I could say."

It wasn't always easy to follow through on the commitments they had made while planning. Some ideas sound great in theory and feel more challenging in execution.

The night the family arrived in San Antonio, they visited the Riverwalk and enjoyed a late dinner. No one got much sleep, and they did tourist activities the entire next day in the heat. That evening, they had committed to working a family fair night at the local art museum.

"If we were in full vacation mode, we would have probably done nothing. Sat in the A/C, maybe gone to get some ice cream," said Chris. "Getting ready, everyone was very quiet. It was clearly not what people would have chosen to do in that particular moment."

But once they arrived, the energy from the crowd and the event lifted them. The times they would have rather slept in or spent an extra hour by the pool were outweighed by the payoff of being involved in the local community in a way they couldn't be as tourists.

Holden met a man from Colombia at the refugee center and they found a soccer ball at the house. They played soccer together for an hour in the backyard.

His father said they go to their different projects with the intent of giving to others. But invariably, people keep giving back to them.

I took one last look in the empty backseat and saw a vision of double car seats.

It's been years since those strapped-down seats left indentations in the leather. The backseat, now spotless, never looked so clean during the car seat years. Even when our daughter outgrew the front-facing seat and graduated to a booster, and when her brother caught up with a booster of his own, it was never a clean car.

Once, I offered a ride to a couple of colleagues when we were headed to lunch. I tossed aside one of the boosters to make space, and was so personally disgusted by the crumbs, spills and stashes of whatever the children were collecting at the moment that I had to lay something down for my co-worker to sit on.

It was that kind of car -- covered in the filth of babyhood, then childhood.

The "classic silver metallic" Prius was pristine, of course, when I fell for her nearly seven years ago. I knew she was the one before I laid eyes on her. I was already sold on the gas mileage, and my last car had been totaled in an accident. Back then, she was still a bit of an oddity in the heart of the Midwest, and people would stop to ask me questions about her in parking lots.

I bragged about the 50 miles per gallon whenever I had the chance. I had been warned of the dangers of "smug pollution" that came with driving this hybrid, but I didn't care if I fell victim.

My children were on the cusp of those busiest chauffeuring years when we got her. Soon enough, she was carting them to preschools and piano lessons and Sunday school and practices. Parents of children of a certain age spend many of their waking hours in a vehicle.

Pri was a reliable companion. We criss-crossed half the country with her. Despite the ever-present evidence of small children inside, I took care of Pri like she took care of us.

When I crossed the 100,000 mile mark, I took a picture of her odometer the same way I documented the children's kindergarten graduations. Even before this milestone, my husband had started suggesting perhaps her time had come. I bristled at the idea.

I didn't need a new car. I preferred to drive this one. Maybe not forever, but certainly for many more years. For the better part of a year, I resisted, and the car became a standoff.

Humans can form attachments to objects, and we are especially susceptible to vehicles that symbolize our freedom, express our identities and transport our precious cargo.

I remember the black Caprice Classic of my childhood, a boat of a car with a rear window space large enough for a small child to lie down in, pressed against the glass. (It was an era of lax child seat safety, I suppose.)

It wasn't just Pri that I loved. Her history was inextricably tangled with the story of my kids' childhoods. For more than 107,000 miles we inhabited this compact space together.

Maybe I wasn't ready to let that go.

But rationality bested sentimentality, as it rightfully ought to in matters of safety.

Earlier this month, I took Pri to a Toyota dealership. Like a man with a midlife crisis, I was literally trading in my steady, faithful companion for a newer, fancier model.

The heated seats and HD radio felt more like a betrayal than a bonus.

I told the salesman and finance guy to make sure she went to a good family. They humored me as they closed the deal.

I filled a couple of Ziploc bags with the loose clips, pens and papers I forgot to take out of the dash.

I took two pictures of her before I walked away. Then I drove off the lot in another Prius.

If she lasts as long as her predecessor, she'll be the one that sees my girl move from the back seat to the front -- and the day soon after, when she takes the wheel.

However imperfect, Congress found a bandage last month for the student loan crisis in the making. Interest rates on certain subsidized student loans were set to double until a last-minute bipartisan compromise tied them to the financial markets, keeping rates lower in the short-term.

But the real bloodshed awaits.

Those rates could rise as high as 9.5 percent for students and 10.5 percent for parents, depending on how the economy recovers. Looking ahead to future generations of college students is a bleaker picture. If we allow past trends to continue unchecked, we will be pricing out a large swath of middle-class children from what used to be considered a ticket to the American Dream.

There's a two-fold reason why the thought of college makes most parents break into a cold sweat, even if their child is years away from heading off into those four (or six) years of higher education. In fact, the panic may be especially acute in that case, because the impending crisis looks scarier than the one averted.

Many parents hope to be able to send their child to the best college to which he or she earns acceptance. But college costs have escalated beyond the rate of inflation for much more than a decade, and there is no end in sight to controlling that rise in tuition and fees. Meanwhile, real wages for middle-class families have flatlined or declined during the past decade.

"The pain factor for families is higher," said Justin Pope, who had covered higher education for the Associated Press for the past decade and will soon become the chief-of-staff for the president of Longwood University in Virginia.

Simultaneously, a college degree has become even more important to a child's future. Over a lifetime, a young adult with a college degree can earn nearly twice as much as someone with a high school diploma. (How much the investment pays off varies by major and the amount of student debt accrued.)

So, what is a reasonable amount of debt for students and their families to incur for a chance at greater economic stability? As of last fall, the average amount of student loan debt for the class of 2011, for those who took student loans, was $26,600 -- a 5 percent increase from 2010, according to The Project on Student Debt. About two-thirds of college seniors who graduated in 2011 had student loan debt. This reflects the total amount borrowed over the entire four to six years to earn a degree. At this level, it is still a worthwhile investment.

As someone who worked and borrowed her way through college and graduate school, I think it can be helpful for students to have some skin in the game when it comes to funding their college dreams. The post-graduation payment on that level of debt, assuming one can eventually find a job, would not ruin a person's life. And funds borrowed from the federal government offer the protection of the Income-Based Repayment program, which caps monthly payments so they do not exceed 15 percent of discretionary income.

But that debt level does not seem sustainable for future generations. An inherent problem in the economics of education is that we haven't figured out a way, on a mass scale, to teach a classroom of students any cheaper from year to year. The labor costs keep rising. It's also why the price of a haircut or dental work keeps rising: The technological innovations do not increase productivity to make the product cheaper. This may change as more colleges and universities figure out how to incorporate massive online open courses as part of a well-rounded education, but that's still a matter of debate.

There's additional financial pressure on the system because state support for state universities hasn't kept pace with enrollment. States still spend about what they did a decade ago to support higher education, but there are a third more students in the system.

"The only way to preserve whatever affordability still barely exists is for people to hold their public officials -- especially state legislatures -- accountable for providing the funding for higher education," Pope said. "Today, the recognition that higher education is essential is widespread, but the states haven't caught up with that. Until people start demanding more, it's hard to see that changing."

A number of families and students breathed a sigh of relief when Congress finally acted on interest rates.

But many are still holding their breath.