Pledging to give away millions of dollars is easier said than done.

John P. Morgridge made his fortune, estimated at $1 billion by Forbes, as chief executive of Cisco Systems Inc. The 83-year-old and his wife Tashia signed the Giving Pledge in 2010 to donate at least half of it. The task of dispersing the funds has become a full-time job for the next generation.

Morgridge's son John D., 53, and his wife Carrie, 49, head the Morgridge Family Foundation, a Denver-based philanthropy that supports causes like the Denver Museum of Nature and Science and Mile High United Way.

Carrie Morgridge did not grow up in a wealthy family, and the Morgridges were not yet billionaires when she and her husband married in 1991, so managing the resources of a charitable institution has been an education for her. She wrote about her experiences in the 2015 book "Every Gift Matters: How Your Passion Can Change the World."

Reuters spoke with Carrie Morgridge about the life lessons she has learned trying to make the most of the donations her family is able to give.

Q: What money lessons did you learn from your own parents?

A: When I grew up, we were paycheck-to-paycheck. If one thing would have happened, we'd have been out on the streets. That gives me empathy. Right now, we're working on work force development and second-generation poverty elimination. I understand. I get it. Sometimes $50 or $100 can improve a person's life.

My parents taught me if I worked hard I could be anything I wanted to be. I have a really strong work ethic, I think it comes out in philanthropy. I work about 80 hours a week.

Q: What did John's parents pass along to him?

A: John had a paper route, then he worked at McDonald's. He always had a job from a young age, all the way through. It's so important because that gives ourselves value. If everything is given, you have less value for yourself.

Q: When you were first married and not thinking about the family fortune, what was your initial plan?

A: John and I had jobs... we still have full-time jobs, it's just for free. We used to flip houses and were licensed contractors, and I have a degree in interior design. We worked together, and we loved it. I stopped flipping houses, but we still own high-end rental properties.

Q: What made you decide to shift to philanthropy?

A: Some families think it's a burden - but the way John and Tashia approached it with us, it's a gift. We don't feel the burden at all. It all comes back to how they allowed us this autonomy. After going to some Giving Pledge meetings, the difference between us and other families is that we are encouraged to be creative.

Q: How do you keep that spirit going in a family?

A: There are six grandchildren, all third generation. They are highly educated and have jobs. Some are going back for their masters. Our son and daughter are 24 and 23, and they live on their own. There is no support. They wash their own cars and do their own laundry. They are adults.

Q: What do you expect the family foundation to look like down the road? Will you eventually give it all away?

A: John's parents gave John and me the opportunity to spend down the assets or grow them. We decided on grow. We're handing it to our kids with the same exact rule, but we won't let them decide until they are older. We'll get them involved around 30, and they can make that choice.

Q: When there is a fourth generation, what values do you want to pass along to them?

A: To be a good person. To give from the heart. To work hard and be nice. Never take anything for granted and live every day like it's your only day.

Q: One of the hallmarks of your foundation is that you do not accept unsolicited applications for grants - you find the causes you want to help. What has that taught you?

A: It's OK to say no. Nobody had ever told me that before. We had to learn it. You only have so much money, and you really have to learn to thoughtfully say no.

I still get 10 to 20 unsolicited requests a week. Our way is to point them in another direction.