Depreciation is a term used in accounting, economics and finance with reference to the fact that assets with finite lives lose value over time (from Wikipedia), I this case, I'd like to discuss CodeDepreciation and its relationship with Optimization and Mantainability by proposing the following rule:

''If code is written for performance (compromising maintainability), the value of such performance optimization (and maintenance degradation) will depreciate, because the likehood of having either faster hardware or different developer maintaining the code increases as time passes.''

On the other hand, maintaintable code, increases its value for similar reasons:

''If code is written for maintainability (postponing performance enhancements), the value of that maintainability (and performace degradation) will increase its value, because the likehood of having either faster hardware or different developer maintaining the code increases as time passes.''

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''On the other hand, maintaintable code, increases its value for similar reasons:''

Or, perhaps, it just depreciates at a much slower rate than non-maintainable code.
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See also RulesOfOptimization, OldCodeRusts, BitRot
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CategoryCoding