One of the great challenges of modern life is avoiding distractions.

In our daily lives, we are flooded by breaking news, music on planes, ads in taxis and little numbers, gazing up at us from phone apps, saying that somebody has something to say. In the investment world, we are bombarded by scrolling tickers, new products and jargon, impenetrable financial reports and the analysis of every twist and turn of government policy.

The key, of course, is not to get distracted by things that are not important. One of those things is the money supply.