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Coding fast vs fast code

Code that executes quickly is part of coding efficiently, but there's a trade-off: Writing fast code is typically time-consuming.

Is It Worth the Time?

The comic (xkcd 1205 ) shows the maximum amount of time you can spend optimizng a task before it becomes inefficient by how much time you are saving and how often the task is run, over a 5-year horizon.

  • If you do a task once a year and you will only save one minute, then the most time you should spend on making it faster is 5 minutes.
  • But if you do it several times a day, say 5/day, then it might make sense to spend up to 6 days making it faster.

In practical coding situations the trade-off is seldom so clear-cut, but the exact idea does apply. It makes little sense to spend a long time optimizing code you will only run a handful of times. By contrast, if you expect you will have to run it often then making it run faster might well be worth the investment.