Business plans may target changes in perception and branding by the customer, client, taxpayer, or larger community. When the existing business is to assume a major change or when planning a new venture, a 3 to 5 year business plan is required, since investors will look for their investment return in that timeframe.
That doesn’t mean you have to bust out Word and start the plan from scratch. A template is great--you probably aren’t doing anything that hasn’t been done before, so it provides a proven structure for your plan. Pretty much everything on it can be customized.
Start from the very beginning understanding that your business plan ought to be specific to your business needs and objectives. Every business ought to have a plan, but not every business needs a full formal plan with carefully crafted summaries and descriptions.
Set yourself a reminder to review your business plan regularly. If you have a team in your business, holding brainstorming sessions is a good way to benefit from their knowledge - it ensures you are all on the same page and that you get their support.