Should intangible assets always be amortized over their legal lives?

The literature makes a distinction between intangible assets with determinate useful lives (e.g., a patent) and those with indeterminate useful lives (e.g., goodwill or (sometimes) part of research and development).

Some intangible economic assets do exist, but are not recognized by Accountants at all because they cannot be measured, and a future benefit flowing from them is not reasonably certain. For example, the combined talent of the company's employees is such an asset. However, the benefit that results from that talent cannot be measured, and future benefits cannot be reasonably expected because these employees are free to quit at any time.

Some intangible assets don't have legal lives, or even determinable useful lives.

For example, there are differing opinions regarding the amortization of purchased goodwill (the difference between the price paid for a purchased business and the total fair market value of the business' net assets. Some countries' accounting rules do not permit the amortization of purchased goodwill: some do, but there is no such thing as the legal life of purchased goodwill, so if it is amortized, it is amortized ober an arbitrary number of years.

Where an intangible asset has a determinable legaluseful life (for example, a patent), it is amortized over its legal life.