I am always in favor of planning things carefully well in advance. Because, in today's competitive world, if you do not plan early, you miss many opportunity. For example, if you plan to travel to a place, then you should book your flight / hotels at least 1/2 months before. Its better if you can even do it even more earlier. Because many prefer to plan early, thus availability reduces, as the day approaches. And that ultimately increases the price as well.
This whole world is a demand supply game. If demand is more, then that causes the price to increase. I have seen the flight ticket prices are much lesser, if you book them 4-5 months earlier, and they keeps on increasing as time progresses.
So its always good to plan ahead , but there are certain situations, which is not in your control, for which you cannot plan before. So we need to face them as they come with patience and try to do our best.