If we have a correct theory but merely prate about it, pigeonhole it and do not put it into practice, then that theory, however good, is of no significance.
Mao ZedongA strategic plan based on the over-all situation of both belligerents is ... more stable, but it too is applicable only in a given strategic stage and has to be changed when the war moves towards a new stage. ... [Conversely, tactical plans may] ... have to be changed several times a day.
Mao Zedong