A mild form of marital conflict often arises at our house when we decide what to put in the donation box for Goodwill-Easter Seals Minnesota.

One of us stubbornly sticks to the argument that just about anything might find a new owner through Goodwill, and that is far better than a landfill.

The opposing, far more sensible view is that sometimes junk really is just junk. So please, let's not force Goodwill to pay people to sort out and pitch that stuff.

The thing is, it is hard to see much real charitable purpose in either of these approaches. We are debating how to get rid of unwanted possessions. The people we are helping are us. And we never forget to grab a donation receipt on the way out, for next spring's tax deduction.

Of course, Goodwill fulfills a laudable mission. But in this season when a lot of us round out our charitable giving for the year, thinking more about the why behind our gifts could make donating a far richer experience.

Think about it, what else besides convenience explains all the canned pumpkin purée that is going to show up at local food shelves over the next couple of months? These cans go to the food shelf because a pumpkin pie didn't get made or a soup recipe didn't quite come together.

Nonprofit leaders are often a little nervous as the calendar turns to December, as almost a third of donations from individuals usually are made in the last month of the year. Nonprofit execs will tell you that they don't really know yet how much the 2017 federal tax law — which has allowed many more Americans to skip itemizing deductions, including for giving away money — will weaken individual donations. The first tax year under the new law showed a slim reduction.

A tax break for charitable donations really does boost donations, and there is no good reason to complain about this.

But my approach to charitable giving hasn't been the same since I first heard a simple lesson a few years ago, when out of town with two dozen teenagers on a summer service trip.

Anyone who has been on one of these should admit that there is a healthy amount of summer vacation baked into them, a week out of town away from parents and with goof-off time in the schedule. Yet it is hard to imagine going through one of these and literally learning nothing.

The lesson that sticks with me came through a program known as DOOR, a faith-based youth program. In Chicago, DOOR runs out of the First Church of the Brethren in the East Garfield Park neighborhood.

It is on the west side of Chicago, where there has been plenty of gun violence in the last few years, including the week we were there.

Yet that doesn't come close to defining this neighborhood. Many of the families appeared to be lower middle class, making their lives there because that is what they could afford in a city with expensive housing.

One evening a program director asked all the high schoolers, from Minnesota, North Carolina and elsewhere, if they had come to Chicago to do charity work? Or to serve people?

In this context "charity" meant what the community groups that DOOR volunteers serve saw all the time. That is middle class or even affluent people coming into a neighborhood to drop off checks and stuff they didn't want any more and then quickly leaving.

Service was different. There might still be some money donated, or even bags of canned food that included pumpkin pie filling. But there was also a commitment on the part of the donor, if not to pitch in, at least not to take off without meeting people who live there.

Our teenagers were assigned to pull weeds out of a community garden and scrape gunk off cafeteria tables at a YMCA family homeless shelter. But they also stayed long enough to get some understanding of how people live in neighborhoods like East Garfield Park and what they might need.

As I was later thinking this through, about how my family spends our own money and time, it is certainly true we are far more engaged in the work of nonprofits where we've also volunteered.

Maybe we only have a superficial understanding of what the people a nonprofit serves really need, but that sure beats no understanding. Or what is worse, a profound misunderstanding.

Here is why it matters: As our understanding increases, we stop giving away money or stuff we can easily spare or don't want anymore. That is, we stop thinking about us. Instead we are donating money and stuff we know other people really need.

This idea was powerfully reinforced this past August on a bus tour of Minneapolis for donors and board members of the affordable-housing nonprofit Urban Homeworks. The tour included a stop at the house of new homeowner TeCara Ayler.

After Ayler told her story of perseverance leading to homeownership, someone asked what advice she would have for Urban Homeworks volunteers and donors.

"Don't just know what you know from the TV," she said. "Go into your city and talk to people."