when businesses amortize expenses over time they help tie the cost of using an asset to the revenues that it generates in the same accounting period in accordance with generally accepted accounting principles gaap for example a company benefits from the use of a long term asset over a number of years thus it writes off the expense incrementally over the useful life of that asset 
the amortization of intangibles is also useful in tax planning the internal revenue service irs allows taxpayers to take a deduction for certain expenses geological and geophysical expenses incurred in oil and natural gas exploration atmospheric pollution control facilities bond premiums research and development r d lease acquisition forestation and reforestation and intangibles such as goodwill patents copyrights and trademarks 2the irs has schedules that dictate the total number of years in which to expense tangible and intangible assets for tax purposes 