Warren Buffett: All investing is laying out cash now to get some more back in the future. The concept of “a bird in the hand” came from Aesop in about 600 BC. He knew a lot, but not that [he lived in] 600 BC. He couldn’t know everything. [laughter] The question is, how many birds are in the bush? What is the discount rate? How confident are you that you’ll get [the bird]? Et cetera. That’s what we do. If you need to use a computer or calculator to figure it out, you shouldn’t [buy the investment]. Those types of [situations] fall into the “too-hard” bucket. It should be obvious. It should shout at you, without all the spreadsheets. We see something better.
Charlie Munger: Some of the worst business decisions I’ve seen came with detailed analysis. The higher math was false precision. They do that in business schools, because they’ve got to do something.
Source: BRK Annual Meeting 2009 Bruni Notes
In 2005, Buffett also says, “I don’t do DCF”. He says he does a rough approximation in his mind.