Several factors can affect the value of a business, including the company's financial performance, growth potential, market share, brand reputation, customer base, intellectual property, assets, and liabilities. The industry and market conditions also play a significant role in determining the value of a business.

Business valuation can be conducted by financial analysts, certified public accountants, appraisers, and other professionals who specialize in this area. Business owners may also choose to conduct their own valuation, although it is recommended to seek professional advice.

The length of the business valuation process can vary depending on the complexity of the business, the availability of data, and the chosen valuation method. Generally, it can take anywhere from a few weeks to several months to complete the valuation process.

Some common mistakes to avoid in business valuation include using outdated or incomplete financial data, failing to consider the impact of market trends and competition, and relying too heavily on a single valuation method. It is also important to work with a qualified and experienced professional to ensure accuracy and avoid biases.

There is no hard and fast rule on how often a business should be valued. However, it is generally recommended to have a valuation conducted at least every two to three years or when significant changes occur, such as a change in ownership, significant growth or decline in revenue, or a merger or acquisition.