Valuing a business is notoriously difficult. While some companies will be happy to put a value on your business based on generalisations such as the sector you work in, it is only through a thorough examination of your specific business that an accurate valuation can be given. While your current and historic financial performance, the sale prices of other comparable businesses, and the health of the industry you operate in, can lead to a valuation being given, you should always bear in mind that a valuation is just an estimate; the true value of your business is ultimately decided by the buyer.
While receiving a high valuation for your business may well be flattering, it is important to have realistic expectations of what your business could hope to achieve. By placing your business on the market at an inflated price could deter those who would be interesting in purchasing for a more realistic price, and could also lead to disappointment when you inevitably have to lower your expectations to complete on a sale.