I have always kept an up-to-date business plan until one day when I added up all of the that I had spent working on my business plan. . . It's possible to over think things and never execute. Now I test market EVERYTHING. The tests results are what guide our business. Business moves fast in 2012. While you're writing your plan somebody else is executing your idea. edit

iPhone app seems to be buggy and deleting words - sorry. The missing word above is "time". edit

Business planning is part science and part art. I see many plans that look great on paper, yet are unrealistic and therefore completely useless. I think market research and analysis are common failure points of most business plans, since most entrepreneurs cherry pick their market research so the data supports their view. It is far better to start with a realistic assessment of the marketplace and adjust the business early on than invest tens or hundreds of thousands of dollars chasing a dream that had very little chance in reality. and waste years of your life.

In my experience, some people do spend too much time planning. But over-planning is by far the exception, not the rule. Most entrepreneurs under-plan, launch too early with too little capital, and then flail around for years. But over-planning can be just as bad, especially for fast moving tech areas like phone apps. In such cases, there is a limited window of opportunity. And if you don't get in early enough, the window closes.

he long and the short of it is: you still need a plan. Just don't get so obsessed with the planning process that you forget to execute! edit

Well said Ajay and Andrew. I agree whole heartily to both points. Often I find an Executive summary is sufficient enough to run a small UNBAISED feasibility study to get the ball rolling.

Andrew, you are highly perceptive to recognize the cherry picking scenario that is so often true and almost invariably overlooked. I can tell instantly from that statement that you've been around the block a few times. I can't stress enough how important it is for founders to not get emotionally attached to a concept, and be blinded by their vision. I don't try to prove concepts anymore. I used to - but now I try to kill them as fast I can so if it doesnt have legs, i can realize that now, and get on with my life, without dragging others into my dillusional sunset. Disproving a concept is how I maintain a neutral mindset. If it survives the bullet test, then it's worth investing some time thinking about. The exec summary starts to grow then eventually becomes a business plan, but not before it proves worthy of my time. Life is too short to waste time, and it's inconsiderate to waste investors' and partners' time.

One of my biggest peeves is when a founder quotes statistics regarding the size of an industry. Just because the industry is valued at a $trillion doesn't mean your concept is likely to succeed. The last I checked, most business schools are still teaching to pitch this way. edit

The best business plans that I see are the ones that document not only what an entrepreneur knows, but what they don't know. All business plans are full of assumptions and the best plans document those assumptions and the plans for validating the assumptions.

Ideally, the planning process is an ongoing part of management, not just a one-time event for fundraising. As assumptions are validated or invalidated, new learnings can be documented in the plan and forecasts can be tweaked to reflect the latest information. edit

I am a bit biased because I am a SCORE mentor, but I think business plans also have to contain a well-thought out financial projections section. I met with a new client yesterday who had listed several expenses and proposed prices for services in a WORD document, but because a word-processing document is static, it doesn't tell you anything about tax consequences, whether you'll actually make any money or give you a chance to try other scenarios. My chapter has a terrific worksheet available free: www.scorela.org, Resources tab. It will the calculations and give you five years of financial projections. Try it if you haven't done more than just list expenses and prices. edit