A "window of opportunity" is that period of time in which suitable action can achieve success ...
For example, there may be a trade-off between the time it takes to create a business plan the window of opportunity for that particular business venture. Too much time planning and the opportunity may be missed or addressed by the competition ... not enough time planning and the approach to capitalizing on the opportunity may not be appropriate. After the window of opportunity closes, the opportunity ceases to exist. Since most opportunities do not last forever, the window of opportunity is the ideal time to act.