“I don’t know when to buy stocks, but I know whether to buy stocks,” said investor Warren Buffett on a CNBC interview. Buffett recently celebrated his 88th birthday and promoted the idea that even though the stock market is at record highs today most investors are still better off owning a basket of diversified equities than long-term bonds. The reasoning is that 30 year treasuries are currently yielding about 3%. But the strong U.S. economy can bolster corporate profits and return more than 3% a year to investors over the next 3 decades on average.

The higher cost of trade tariffs and current economic and political issues facing the U.S. and the world today are transient and we have to think about long term strategies to win the long game. Buffett is convinced that “business is good across the board,” he added. Berkshire Hathaway, the company he manages, has more than 90 businesses in the insurance, energy, food and retail, industrial and other sectors, and invests in companies such as Wells Fargo & Co (WFC) and Coca-Cola Co (KO).

One popular stock that Buffett bought for his investors is more Apple Inc. (AAPL) This might be surprising to some readers because the Oracle of Omaha has been known to stay away from technology stocks for most of his investment career. Earlier last month, Apple became the first publicly traded U.S. company to reach $1 trillion in market value. Berkshire Hathaway is the second-largest holder of Apple shares with a stake worth about $56 billion, according to FactSet.

Buffett claims that he does not focus on the sales in the next quarter or even the next year. What’s more important to him is the hundreds of millions of people who practically live their lives by Apple’s core product, the iPhone. To him the iPhone is “enormously underpriced,” based on its utility, saying it’s actually worth far more than the $1,000 it costs people to buy it. As a comparison he mentions that his private plane costs him maybe a million dollars to maintain every year. But he gets more use out of his iPad which costs a lot less than his plane. So he would easily give up his plane and many other conveniences around him before considering not spending money on a handheld device. Buffett concludes that the reason the iPhone isn’t a lot more expensive than $1,000 is because of competition.