Share your insights or perspective on the financial matter presented in the input.

When following a buy and hold investment strategy, on what conditions should one sell?
Buy and hold doesn't have an exact definition, as far as I know.  In my opinion, it's offered as a contrast to those who trade too frequently, or panic every time the market drops 2%.  For the general market, e.g. your S&P index holdings. You sell to rebalance to your desired asset allocation. As a personal example, at 50, I was full up invested, 95%+ in stocks. When my wife and I were retired (i.e. let go from company, but with no need to go back to work) I started shifting to get to a more sane allocation, 80/20. The ideal mix may be closer to 60/40.  Also, there are times the market as a whole is overvalued as measure by P/E and/or CAPE, made popular by Nobel Prize winning Robert Shiller. During these times, an allocation shift might make sense.  For the individual stocks, you had best have a strategy when you buy. Why did you buy XYZ? Because they had promise, decent company with a good outlook for their product? Now that they are up 300%, can they keep gaining share or expand their market? Sometimes you can keep raising the bar, and keep a company long term, really long. Other times, the reason you bought no longer applies, they are at or above the valuation you hoped to achieve.  Note - I noticed from another question, the OP is in the UK. I answer this my from US centric view, but it should still apply to OP in general. The question was not tagged UK when I replied.