For most banks, the financial crisis was an unmitigated disaster, causing hundreds to fail and thousands others to egregiously dilute their shareholders. But for Wells Fargo (NYSE:WFC), and a small handful of others, it served as a potent catalyst that allowed them to surge ahead of the competition.

For its part, Wells Fargo more than doubled in size thanks to the acquisition of its bigger but less-prudent peer, Wachovia. And as lenders like Bank of America and Citigroup were forced to retreat and retrench, Wells Fargo stepped into the void and consolidated a dominant position in the massive market for U.S. mortgages.

How was it able to do so? The answer is simple: Wells Fargo has a long and well-documented history of responsible management. Unlike its too-big-to-fail peers, the California-based bank has cultivated a culture of thrift when it comes to expenses and excess when it comes to risk management. And by constantly nurturing talent from within, it's inculcated that culture in successive generations of leaders.

It's with this in mind that I recently spent a day rereading the last 20 years' worth of the shareholder letters written by various Wells Fargo chairmen and CEOs. What follows are seven valuable insights I've condensed, accompanied by quotes from the letters about them, that both investors and bankers can glean from one of the best-run banks in the country. 

1. To be the best bank, you have to be the best risk manager

"In financial services, if you want to be the best in the industry, you first have to be the best in risk management and credit quality. It's the foundation for every other measure of success. There's almost no room for error."

2. Bigger isn't always better

"Many 'banks' have learned the hard way: Bigger is not always better. You cannot simply acquire your way to success. You get bigger by being better. You don't get better by being bigger."

3. Any bank can have a vision; what matters is execution

"A vision by itself is not enough. You must have a plan to achieve that vision and a time-tested business model that can perform successfully in any economic cycle. You have to execute against that plan efficiently and effectively. In fact, it's all about execution. To be successful, you need leaders who can establish, share, and communicate that vision, motivate others to embrace, believe in and follow that vision, and execute in a superior fashion each day, every day, one customer at a time."

4. Success requires restraint

"Because of our prudent lending to customers with less than prime credit and our decision not to make negative amortization loans, we estimate we lost between two and four percent in mortgage origination market share from 2004 to 2006. That translates into losing between $60 billion and $120 billion in mortgage originations in 2006 alone. We're glad we did. Such lending would have been economically unsound and not right for many borrowers."

5. Money never declines; it just moves

"One reason we've been able to consistently deliver strong results for nearly two decades in all economic cycles without taking undue risk is because we have one of our industry's most effective, time-tested business models. It's not product-centric but customer-centric, and it's diversified, including virtually all financial products and services. It's based on our belief that money never declines. It simply moves from one segment or investment vehicle to another, in response to macroeconomic factors and our customers' own life cycles. From CDs and annuities to mutual funds and stocks and back. Our customers go from net borrowers early in life to net investors later in life. From life insurance to investments, from secured credit to unsecured credit. Keep[ing] our customers' business as they decide to move their money is how we've avoided volatile earnings through booms, busts, expansions, and recessions."

6. It's important to be consistently trustworthy

"It's impossible to earn trust if one is trustworthy in some things and not trustworthy in other things. We have to be trustworthy in all things all the time. The word 'integrity' and the word 'integration' come from the same root: entire. This implies a wholeness, a complete, undivided, unbroken consistency of approach and execution. To have integrity one must be consistently honest and trustworthy in everything one does. When you have integrity, people know you will do what you know is right. And that happens to align with how we define 'culture' at Wells Fargo. It's knowing what you have to do without someone telling you to do it. That's why integrity is not a commodity. It's the most rare and precious of personal attributes. It is the core of a person's -- and a company's -- reputation."

7. Banks must reinvent themselves to survive and thrive for multiple generations

"It's a rare company that outlives the average human being. Our company has survived and prospered about twice that. How did we do it? By constantly reinventing ourselves. Wells Fargo has survived for 150 years -- from stagecoaches that went 5 miles an hour to email at 30,000 miles a second -- because it's been a uniquely capitalistic enterprise. From decade to decade it has not been afraid to take advantage of 'creative destruction'. It has continually adapted new technology to create better ways to save customers time and money."

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.