Intangibles represent the use of cash to purchase assets with an undetermined life and they may never mature into cash. For most analysis purposes, intangibles are ignored as assets and are deducted from net worth because their value is difficult to determine. In several respects, intangibles are similar to prepaid expenses; the use of cash to purchase a benefit which will be expensed at a future date. Intangibles are recouped, like fixed assets, through incremental annual charges (amortization) against income. Standard accounting procedures require most intangibles to be expensed as purchased and never capitalized (put on the balance sheet). An exception to this is purchased patents that may be amortized over the life of the patent.