Long term planning with the proper analysis is critical for any project. In my recent interactions with various groups, I understood the importance of planning very well, not because it was done properly but rather because of its absence.
An absence of proper planning leads to havoc every time. The people involved have to work extra hours, the deadline is missed several times and nobody is appreciated for putting the extra work since they already missed the deadline in the first place. All of this happen because the upper management couldn’t plan it well.
In my early corporate days at TCS, we were obsessed with planning and since TCS was the first company it also got me into thinking that TCS guys plan for too long (which is partially true also). The upside of that strategy, however, is that we seldom had panic moments in the project life cycle in those days. Everything was so well planned that it led everyone to believe that its the natural state in IT.