There's a comfortable assumption that understanding, once built, stays built. It doesn't — and it's worth knowing, because it changes the timing of the decision.
What Actually Degrades
Language knowledge stored as facts — vocabulary, grammar rules, meanings — decays without use. Not catastrophically and not evenly, but steadily.
You'll have noticed this with a school language. Five years of study, and what's left is a handful of phrases and a general sense that you'd recognise things if you heard them. The material didn't vanish. It became progressively harder to reach.
That's the same store your current understanding sits in, and it's subject to the same process.
Why This Matters for Timing
The material you built through input is the raw material for production practice. It's what gets converted.
Which means the conversion is cheapest now and gets more expensive the longer the store sits unused. A phrase you'd recognise instantly today takes a few listens to make automatic. The same phrase after three dormant years takes longer, because you'll be partly relearning it before you can automate it.
There's no cliff and nothing dramatic happens. The work simply gets slowly harder while nothing else improves.
What Survives
The distinction matters. Anything that reached genuine automaticity is durable — it behaves like a physical skill and comes back quickly after long gaps.
Anything still sitting as knowledge is the perishable part. So the practical effect of converting some of it now is that you move material out of the fragile store and into the durable one.
That isn't an argument for urgency. It's an argument about which direction the value is moving.
The Plain Version
You currently hold an asset that took years to build, it's fully retrievable, and it's precisely the input the next stage needs. It'll still be there next year, slightly diminished. And the year after, slightly more so.
Converting it is cheapest at the point where it's freshest.
About Outputly
Outputly converts existing understanding into automatic speech. The more retrievable your vocabulary is, the faster the conversion goes.