Here's a view which coincides with what I've been thinking for some time (and therefore may be an example of extreme confirmation bias on my part ). Jim Rogers, co-founder with George Soros on the Quantum Fund says: "diversification is just something that brokers came up with, so they don't get sued. If you want to get rich ... you have to concentrate and focus." https://news.thestreet.com/independ...ogers-on-why-not-to-diversify-portfolios.html In this view, it's not all about length of time in the market. That'll just get you plodding returns (like the 2% my pension returned in the last year). My big gripe, though, is that diversification doesn't actually protect you. Yes, it'll save you from company- and industry-specific risk, but as long as you steer clear of stupid stuff the biggest risk by far is market risk which you can't really protect against. So looking out for value buys and concentrating on a very small number of stocks seems to me to be reasonably sensible. So far I've managed to make a return of about 20% in six months while testing this strategy, though obviously that is much too short a time period to draw any inferences.