Getty ImagesReady to reflect.We’ve learned all about Warren Buffett’s alarming dietary habits, but what will the Oracle of Omaha reveal when he releases his annual letter this weekend? The missives have become an annual midwinter rite for hard-core Buffettologists and regular investors alike, but this year’s letter is special because it marks the 50th anniversary of Buffett’s purchase of a struggling New England textile maker known as Berkshire Hathaway BRK.A, -0.48% BRK.B, -0.63% The 84-year-old Buffett appears to be in a particularly reflective mood. In December, he said he had already composed around 20,000 words, or around 30 pages, according to The Wall Street Journal, though that’s before editing (Buffett’s letters usually run to around 14,000 words, according to Bloomberg). Here are 4 things to watch for:Mistakes One thing successful investors and traders love to talk about is their past mistakes. This might seem counterintuitive, but successful investing relies on discipline, particularly limiting losses and bouncing back from errors. Many are more than eager to describe the lumps they took on the way to mastering their craft. Buffett’s no different. In a section of his 1989 letter, Buffett described the “Mistakes of the First Twenty-Five Years.” “We hope in another 25 years to report on the mistakes of the first 50. If we are around in 2015 to do that, you can count on this section occupying many more pages than it does here,” Buffett wrote at the time (h/t: Ben Carlson).Succession This is a question that never goes away. Buffett says he and the Berkshire board have agreed on who will succeed him as CEO and two backup candidates as well, but he’s never revealed their identities. Needless to say, much attention is heaped on investment managers Todd Combs and Ted Weschler, who were brought on board in 2011, and are widely seen as potential successors. Buffett might take the opportunity to ruminate further on the succession question, but don’t expect him to identify the heir-designate.Cash hoard Berkshire Hathaway is flush with cash, sitting on $62.4 billion as of Sept. 30. Investors will seek clues to how Buffett plans to deploy the money. Investors are wondering if Buffett is set to begin a European adventure after Berkshire’s purchase earlier in February of a German retailer. He told a German newspaper that he was “definitely interested in buying more German companies,” according to Reuters.Downside of size It will be interesting to see Buffett’s latest thoughts on the perils of being a behemoth. As the old saying goes, size can be the enemy of performance. With a massive portfolio, it’s more difficult to be nimble. “Because of our present size, making acquisitions that are both meaningful and sensible is now more difficult than it has been during most of our years,” Buffett lamented in his 2012 letter. Take it with a grain of salt, however. Buffett, in his first letter in 1965, was worrying that the partnership was already in danger of becoming too big, notes FT Alphaville. William Watts