text: Characteristics related to useful life are that has an indeterminate or an unpredictable useful life because of the unusual manner in which it is used , improved , retired , modified , or maintained or is at a very high risk of being destroyed during use or of premature obsolescence .
  
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  The length of a useful life depends on how it is used , modified or maintained and unpredictable use can lead to a higher risk of it being destroyed prematurely .