The valuation of an intangible asset is based on its useful life. For trademarks, appraisers regularly opt for an indefinite life, when no obvious factors exist that would limit the future economic life of the trademark. Almost all brands are however finite, and assuming indefiniteness can have two serious effects: one on value and one on accounting. The following article discusses such effects and suggests some guidelines and tools for how to analyse the life cycle of a brand and how to estimate its remaining useful life (RUL).