Don't read any book you've read before. Don't read any author you've read before. Don't visit any website you've visited before. Don't play any game you've played before. Don't listen to familiar music that you already know you'll like. If you go on a walk, walk along a new path even if you have to drive to a different part of the city for your walk. Don't go to any restaurant you've been to before, order a dish that you haven't had before. Talk to new people (even if you have to find them in an IRC channel) about something you don't spend much time discussing.And most of all, if you become aware of yourself musing on any thought you've thunk before, then muse on something else. Rehearse no old grievances, replay no old fantasies.
The comments and its reposting to MR suggests that this is popular advice.
It's interesting that, despite the warm reception, this idea needs pointing out, and trying for one experimental day.
Having habits for things like brushing teeth is useful - the more automatic uninteresting or unenjoyable experiences are, the more time and thought can be devoted to other things. Habits for places to go could be argued for - if you love an experience, why change it?
But why should we want to repeat thoughts a lot? Seems we say we don't. So, why do we do it? Do we do it? If we can stop when Eliezer suggests it, why don't we notice and stop on our own? Is it that habits are unconscious; a state that doesn't lend itself to noticing things? Has the usefulness of other habits made us so habitual that our thoughts are caught up in it?
What can we do about it?
As a side note, perhaps the quantity of unconscious habit in a life is related to the way time speeds up as you age.