1205: Is It Worth the Time?

Explain xkcd: It's 'cause you're dumb.
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Is It Worth the Time?
Don't forget the time you spend finding the chart to look up what you save. And the time spent reading this reminder about the time spent. And the time trying to figure out if either of those actually make sense. Remember, every second counts toward your life total, including these right now.
Title text: Don't forget the time you spend finding the chart to look up what you save. And the time spent reading this reminder about the time spent. And the time trying to figure out if either of those actually make sense. Remember, every second counts toward your life total, including these right now.


The comic is a straightforward chart showing the amount of work (time) one can dedicate to making a task more efficient, in order not to spend more time optimizing the task than the total time saved. This may illustrate the fact that computer scientists often try to optimize tasks they are likely to perform again in the future (since this is a common goal in their work), even though the work needed for that optimization can itself prove much longer than the time saved when doing the task again; this was previously referenced in 974: The General Problem.

E.g. if you do some task every week once, and you are able to save 1 minute of time by doing some preparatory work (e.g. build or buy a tool), you can spend 4 hours doing this preparatory work, and you will, across five-years time, come even. (Any less time spent doing the preparatory work, and you will profit from it.)

The calculation on which the chart is based, for this example:

5 years / 1 week = 260 occurrences of the task
260 occurrences × 1 saved minute = 260 saved minutes = 4.3 hours

Therefore, 1 minute saved every week would, across five years, save over 4 hours of your time.

Or, in algebraic form:

Total time shaved off across 5 years = 5 × “How often you do the task every year” × “How much time you shave off”

The blacked out areas represent times which are impossible to save (e.g. it is impossible to shave 1 hour off a task if you perform 50 times a day – the total time shaved off per day would amount to 50 hours, far more than the 24 hours a day).

The comic derives humor from the absurd conclusions of hyper-efficiency, which have been examined in http://what-if.xkcd.com/22/. The title text points out the time you spend studying this comic detracts from your overall efficiency, and concludes that maximizing efficiency would require optimal use of every second.

One more comic devoted to insufficient economy is 951: Working, where the money saved is compared to the time wasted while looking for a bargain.


How often you do the task
50/day 5/day Daily Weekly Monthly Yearly
How much time you shave off 1 second 1 day 2 hours 30 minutes 4 minutes 1 minute 5 seconds
5 seconds 5 days 12 hours 2 hours 21 minutes 5 minutes 25 seconds
30 seconds 4 weeks 3 days 12 hours 2 hours 30 minutes 2 minutes
1 minute 8 weeks 6 days 1 day 4 hours 1 hour 5 minutes
5 minutes 9 months 4 week 6 days 21 hours 5 hour 25 minutes
30 minutes 6 months 5 weeks 5 days 1 day 2 hours
1 hour 10 months 2 months 10 days 2 days 5 hours
6 hours 2 months 2 weeks 1 day
1 day 8 weeks 5 days

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The title text is just silly. 08:52, 29 April 2013 (UTC)

Is it worth all of the time we've spent on 1190, developing wikis, and wget scripts to pull the pictures efficiently, etc.? Bdemirci (talk) 08:58, 29 April 2013 (UTC)

I would just like to ask if there is an interactive version of this comit out there. I suppose it wouldn't be too hard to create... --Charlesisbozo (talk) 09:14, 29 April 2013 (UTC)

Well, it would be really simple indeed. For now, you can try Wolfram|Alpha --Mormegil (talk) 10:49, 29 April 2013 (UTC)
I have a site up that does the calculation : http://c.albert-thompson.com/xkcd/ --Whitecat (talk)whitecat (whitecat) 18:39, 29 April 2013 (UTC)
I wish I had seen whitecat's tool before I made my own. It's slightly different, so that's good: http://agileadam.com/worth-automating/ --Agileadam (talk) 18:27, 4 April 2015 (UTC)

The graph ignores the fact that it is much more satisfying to shave off time from task, especially by automating it. Also note that it IS possible to shave off 6 hours from task you do daily and one day from task you do weekly. -- Hkmaly (talk) 10:39, 29 April 2013 (UTC)

The table also ignores all monetary costs associated with the work: e.g. buying a new tool -- 15:45, 29 April 2013 (UTC)

I was thinking the same, but then realised it's NOT practical if you assume a 6 hour working day and 5 day working week. 12:33, 29 April 2013 (UTC)

If Momo taught us 1 thing, than it is that you can not save time ;-). --DaB. (talk) 13:56, 29 April 2013 (UTC)

Why is it "not possible" to shave a day off of a task that you perform weekly? MrBigDog2U (talk) 14:29, 29 April 2013 (UTC)

It definitely possible, but Randall feel it's just not worth the time to put it there. :-) Arifsaha (talk) 16:09, 29 April 2013 (UTC)
Then the explanation is inaccurate as it states that "blacked out areas represent times which are impossible to save". It is possible, perhaps just not worthwhile. MrBigDog2U (talk) 14:35, 30 April 2013 (UTC)

For most people in most circumstances, a net present value comparison would be most relevant. Even if I can save a day every year for the next 5 years, it may not be worth 5, or event 4, days input now, because my time now is more valuable to me than my time in the future (as of now), and my opportunity cost for time spent now greater. It would be interesting to see the chart revised assuming a particular discount factor, and that all efficiency-improvement input occurs up front. RyanDonovan (talk) 17:29, 29 April 2013 (UTC)

     Agreed!    :¬D

TL;DR --DanB (talk) 21:14, 29 April 2013 (UTC)

Reminds me of this chart: http://i.imgur.com/Q8kV8.png And of course, Randall has covered similar ground before: http://xkcd.com/974/Gardnertoo (talk) 16:46, 30 April 2013 (UTC)

There are a few flaws with this:

  1. How many tasks that you were doing five years ago are you still doing? I'd give a max window of two years for most task executions.
  2. Whatever system you designed to save you time will itself require maintenance -- and become a task.
  3. Very few people can figure out when they start a time-saving task how long it will take.
  4. Not all attempts to create a time saving system actually work
  5. Not all attempts to create a time saving task actually save time
  6. Once you create a time saving system, you are locked in to doing the task the way that the time saving system expects you to do it -- or, continually modify your time saving task, which again, takes time.

Dave Edelhart 16:56, 30 April 2013 (UTC)

WRT your first 'flaw'. I can think of lots. Just off the top of my head - brushing my teeth, making breakfast, showering, walking my dog, commuting, responding to emails, editing documents for grammar and style, arguing on wikis, etc... There are thousands of such tasks, if not tens of thousands. 17:47, 18 May 2013 (UTC)

The chart does not take into account when multiple users use the more time efficient task. --Rhayader (talk) 11:20, 1 May 2013 (UTC)

For multiple users who benefit, you multiply the number by the users. But you should recalculate it yourself, because the numbers are floored. Saving 5 seconds daily gives you 2.536111 hours in 5 years (5*365+1 days). So for example, to save a group of 15 people 5 seconds for the twice-a-day coffee break: Randalls 2 hours gives you 2*2*15= 60 hours to spent for a computerized/automated coffee system which saves everybody 5 seconds. While it's actually 76 hours and 5 minutes. :) 15:54, 1 May 2013 (UTC)
For across a tritri years, most things get a byte more well-defined. 10:05, 24 January 2018 (UTC)