51.   The helicopters in question continue to fly until their useful life is ended and they end up on the scrap heap to be cannibalized for their parts.

52.   The mercury is of greatest immediate concern to those involved in the recycling of cars that are at the end of their useful life.

53.   The IRS defines depreciation as an annual deduction available to taxpayers to recover the cost of business or investment property with a useful life of more than one year.

54.   The Pentagon has managed thus far by robbing funds intended for future programs and equipment, but even that tactic has lost its useful life.

55.   Their useful life is relatively short, comparable to the useful life of a flimsy house in a hurricane zone.

56.   These slower chips are made for portable computers, the kind powered by hefty slabs of lithium that generally provide only two to three hours of useful life.

57.   This translates into substantial savings for users and a longer useful life for the satellites.

58.   Those nuclear operators with a good safety record deserve to have their licenses renewed, so that existing plants may run to the end of their useful lives.

59.   To get the absolute best value for the money, a driver should buy a well-built car and hang on to it until the end of its useful life.

60.   Useful life is prolongable.