# deferred maintenance (upkeep)

*Ordinarily means:* Putting off necessary repairs or care until later.

Work that does not happen when a thing is inside its window, so the range of the thing's parameters narrows without anyone seeing the wall that will end it.

- Computed level: L15 (depth in the emergence graph, not abstraction)
- Status: review  ·  Domain: everyday  ·  Arena: emergence

## Emergence
**Emerges from:** [maintenance](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-maintenance.upkeep), [window](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-window.range), [wall](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-wall.range-end), [narrow](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-narrow.spatial), [parameter](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-parameter.condition)

**Through:** passive

**Novel properties:**
- invisible_maintenance

## Examples
- The 2021 Texas power grid failure followed decades of skipped winterization upgrades to generators and pipelines. *(engineering)*
- The USS Thresher sank in 1963 after undetected hull corrosion narrowed safe dive depth below operational limits. *(military)*
- By 2019, 45% of New York City’s subway signal systems were past their 50-year design life, running on deferred replacement. *(infrastructure)*

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*Canonical: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-deferred-maintenance.upkeep*  
*Structured data: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-deferred-maintenance.upkeep.json*  
*Every definition provably resolves to space, time, energy and pattern.*