"We like to own castles with large moats filled with sharks and crocodiles that can fend off marauders -- the millions of people with capital that want to take our capital. “We think in terms of moats that are impossible to cross, and tell our managers to widen their moat every year, even if profits do not increase every year. We think almost all of our businesses have big and widening moats."
"Usually, if something can gain competitive advantage very quickly, it can lose it very quickly, so be careful of industries in flux."
"You will see that we favour businesses and industries unlikely to experience major change. The reason for that is simple: We are searching for operations that we believe are virtually certain to possess enormous competitive strength ten or twenty years from now. A fast-changing industry environment may offer the chance for huge wins, but it precludes the certainty we seek."
"The key to investing is not assessing how much an industry is going to affect society, or how much it will grow, but rather determining the competitive advantage of any given company and, above all, the durability of that advantage. The products or services that have wide, sustainable moats around them are the ones that deliver rewards to investors."
“Experience, however, indicates that the best business returns are usually achieved by companies that are doing something quite similar today to what they were doing five or ten years ago. That is no argument for managerial complacency. Businesses always have opportunities to improve service, product lines, manufacturing techniques, and the like, and obviously these opportunities should be seized. But a business that constantly encounters major change also encounters many chances for major error. Furthermore, economic terrain that is forever shifting violently is ground on which it is difficult to build a fortress-like business franchise. Such a franchise is usually the key to sustained high returns.” by Warren Buffett