1. "Not supporting a friend in her new business"
— Melissa, a consultant from Austin

Money regret: "In my 30s, friends started selling things like Pampered Chef. I would go to the parties and not buy anything. I regret that. My friend was super excited about her business and she thought it was going to take off and she was going to quit her job. I didn't want to feed her false hope. I just didn't buy it. Going back, I would just buy one thing to support her."

Essential lesson: "If there's someone you care about who's selling something, just buy it. Who cares what it is? Today, I would buy anything from anyone."

2. "Chose the wrong major"
— Angie, works in education in NYC

Money mistake: "[I think I chose the wrong major] because I don't like business. Right now, I kind of changed programs. I am working with kids. I realize that I like that better. I spent a lot of money studying business."

Essential lesson: "If you're not sure what you want to study, just take your time and think about it. Because you're going to spend too much money on that. It's something you might be doing your whole life."

3. "Not buying a three-bedroom apartment in 1977 in the Upper West Side for $33K"
— Adriana, a financial adviser from Toronto

Money regret: "The money was in the bank because we would rather have the money in the bank than spend it on something silly like this."

Essential lesson: "To my child, I say 'Listen to your mother when your mother says a very smart way to spend your money is to buy real estate.'"

4. "My ex-husband"
— Christy, a commercial real estate agent from Dallas

Money regret: "I was the breadwinner and my husband took care of the finances and did a lot of spending with it. I probably should have gotten involved more and not just trusted the fact that he was taking care of things, without realizing how much was going out the door."

Essential lesson: "Keep on top of your finances. Don't trust someone you think is taking care of your finances. Just have some knowledge as to what's going on."

5. "Should have started saving earlier for retirement"
— Deborah J. Mitchell, a TV producer from Orlando, Florida

Money regret: "I started seriously saving in my 30s. I should have started in my 20s because time does make a difference with compounding and money adding up later in life. I didn’t realize the importance of saving money and how quickly time goes by.

Essential lesson: "Start saving even if it's a little bit. Start saving earlier."

6. "Shoes"
—Tracey, a government health worker from Brisbane, Australia

Money mistake: "It's been a lifelong tragedy, basically, from when I was a teenager. When I started working, I just thought I could spend more on them. It's the one constant."

Essential lesson: "I would probably be more financially responsible. I was very irresponsible with my shoe buys. Buy high-end, fewer pairs."

7. "Not buying Amazon stock in the '90s"
— Anne, an administrative assistant from Renning, Pennsylvania

Money regret: "I wasn't savvy enough. In your 40s when you're working to survive, you don't have the extra money to buy stock. Now that I'm older and the kids are grown, you have the opportunity and you know what brokers do."

Essential lesson: "Ask for advice, as odd as it is, about things you don't know. Don't be embarrassed. Just go ask somebody. Every company, or every major corporation, they've got people. Go to people you're associated with in the company you work for, and if that's not available, go to your parents. Ask who your parents used. I didn't have the sense to do that and I should have."

8. "Totally too frugal my whole life"
— Peggy, real estate agent from Corpus Christi, Texas

Money regret: "I've been a saver all my life. It's just my nature. My mom was frugal. We jokingly used to call her Deep Pockets because she couldn’t quite reach the money that was in there. I didn't want to be like that but it just came to me. I'm 71 now and I really kind of regret not going for it more so. I remember going to New Orleans with my husband and we kind of looked at this boat that was going to go out. And we thought, "Oh no, it's $40." And we walked away from it and did that on many, many occasions. At the time, convincing myself "Why? It's going to be $40. Why do it?" And now I wish we would have. I thought I was going to change, around 64, and I have to some extent."

Essential lesson: "Go for it. I have changed, I really have, and I'm very proud. Recently, my husband and I were somewhere for dinner and it was like 'Oh, $46 for a steak. Sure!' Five years ago, we would have been like 'What? $46 for a steak?' And now we just do it."