1) A business plan is critical for startups as it helps business owners formulate goals and strategies, and familiarizes potential investors, lenders, and clients with the business concept.
2) While the business plan is primarily developed at startup, it should be updated annually as part of the budget planning process to account for changes in revenues, expenses, and market conditions.
3) Very small businesses like hot dog stands may not need a formal business plan, but for most businesses planning is important, especially as they grow in size and complexity.