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.
If you are seeking finance for your business, you will need to show banks and investors why they should invest in your business. Lenders and investors will only risk their time and money if they are confident that your business will be successful and profitable.
Business plans may be internally or externally focused. Externally focused plans target goals that are important to external stakeholders, particularly financial stakeholders. They typically have detailed information about the organization or team attempting to reach the goals. With for-profit entities, external stakeholders include investors and customers. External stake-holders of non-profits include donors and the clients of the non-profits services. For government agencies, external stakeholders include tax-payers, higher-level government agencies, and international lending bodies such as the International Monetary Fund, the World Bank, various economic agencies of the United Nations, and development banks.
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.