It's easier to deal with the rain when you're prepared. You bring your umbrella and wear your rain boots because you know you'll be doomed without them.
Like a good business plan, it's much easier to deal with industry changes when you're prepared. You look out the window and examine the environment. Is it cloudy out? Is there a shift in technology? You calculate your observations and plan accordingly.
If you don't take the time to examine your environment, it's likely to put a damper on things. Let's learn a lesson from Blockbuster.
