Countless ! Starting from mundane things like coffee vs tea to food habits , political views,… beliefs to metaphysical matters about God and purpose of our existence! To me changing one’s mind just proves that one got a Mind ! There is a famous quote attributed to Keynes ,” When my information changes, i change my conclusions , What do you do , Sir “… The only point I would add is one really should be able to explain one’s reasoning behind changing one’s mind . Most of the time , we make up our mind quite unconsciously based upon a number of assumptions , beliefs and prejudices. And the moment we start evaluating them and we replace those assumptions with facts as far as possible, our views and opinions change too . As G B Shaw pointed out, progress is not possible without change. And one who cannot change their minds cannot change anything . !