TL;DR: When a tool makes tasks faster, you don’t finish sooner and relax. You find more tasks worth doing. You end up busier than before, even though each task takes less time. This is a mechanical outcome, not a failure of the tool. Economics has a name for it.

Someone told me recently that since adopting a productivity system I’d helped them set up, they had less free time than before.

That’s not a bug. It’s a well-understood economic phenomenon.

The Two Effects

When something gets cheaper, two things happen:

The substitution effect: You do more of the cheaper thing, because its relative price dropped. If oranges halve in price, you buy more oranges and fewer apples.

The income effect: You’re spending less on the same basket, so you’re effectively richer. You could pocket the savings.

The two pull in opposite directions. Substitution says do more. Income says relax, you’re ahead.

The Maths

You have two goods: tasks and leisure. Your budget is time.

Tasks completedLeisure timeBefore toolAfter toolABCU₁U₂lostleisure

A → B (substitution effect): The tool made tasks cheaper relative to leisure. You slide along the same satisfaction curve toward more tasks, less leisure. This always happens.

B → C (income effect): You’re “richer” in time, so you shift to a higher satisfaction curve. You get some leisure back.

Net result (A → C): More tasks, and whether you end up with more or less leisure depends on which effect dominates. The Jevons observation is that for productivity tools, substitution typically wins. You land at C with more tasks and less leisure than A.

Formally, the Slutsky equation decomposes the total effect of a price change:

∂x/∂p = (∂x/∂p)|U - x · (∂x/∂m)

The first term is the substitution effect (always pushes toward more of the cheaper good). The second is the income effect (direction depends on whether the good is “normal”). For tasks, both terms push the same way: more tasks. For leisure, they oppose. When substitution dominates, leisure falls.

The person who told me they’re busier isn’t doing anything wrong. They’re at point C.

Applied to Productivity Tools

Before the system: capturing a process, documenting a decision, following up on a thread cost 20-30 minutes of friction each. So most of them didn’t happen. They sat below the threshold of “worth bothering with.”

After the system: the same tasks take 3-5 minutes. Friction dropped by an order of magnitude.

The substitution effect kicks in hard. Tasks that were too expensive to justify are now cheap. So you do them. All of them. You capture things you never would have captured. You follow up on threads you’d have let drop. You document decisions that would have stayed in your head.

The income effect (the freed-up time you should be enjoying) gets eaten by all the newly-viable tasks flooding in from below the old cost threshold.

You’re not doing the same work faster. You’re doing more work.

Jevons Paradox

This has a name. In 1865, William Stanley Jevons observed that James Watt’s steam engine made coal more efficient, and coal consumption increased. More efficient use per unit meant more uses became economical. Total consumption rose.

The same pattern shows up everywhere:

  • Roads: Widen a highway and traffic increases. Induced demand. Trips that weren’t worth the congestion become viable.
  • Storage: Give people more disk space and they fill it. Files that weren’t worth keeping become worth keeping.
  • Communication: Make messaging free and the volume explodes. Conversations that weren’t worth a phone call become worth a quick text.

Productivity tools are no different. Make knowledge work cheaper in time and you get more knowledge work, not more leisure.

The Backlog Was Always Infinite

There was never a finite amount of “work to get done” after which you’d be free. The backlog of things that could be captured, documented, systematised, followed up on, improved is effectively infinite.

Before the tool, you couldn’t see most of it. High friction acted as a filter. Only the most urgent or high-value tasks cleared the threshold. Everything else was invisible, not because it didn’t exist, but because it wasn’t worth thinking about.

The tool didn’t create the backlog. It made it visible.

Claiming the Income Effect

The tool won’t give you free time. You have to take it.

That means deliberately leaving viable tasks undone. Not because you can’t do them, but because the time is worth more spent elsewhere. The tool lowered the cost of each task, but it didn’t change the value of your time. Some tasks are now cheap enough to be worth doing. Many still aren’t.

The discipline isn’t in doing more efficiently. It’s in choosing not to do things just because they’re now cheap enough to do.

That’s the difference between productive and busy.