Run-to-Failure vs Preventive Maintenance
Run-to-failure deliberately operates an asset until it breaks, then repairs or replaces it — the cheapest strategy for low-consequence, easily-replaced items. Preventive maintenance services assets on a planned basis to stop failures happening, protecting critical equipment from costly unplanned downtime. The right choice per asset depends on the consequence of failure, not on a blanket policy.
Run-to-failure sounds like neglect but is a legitimate strategy when applied deliberately to the right assets. Preventive maintenance avoids surprises but costs money and can over-service healthy equipment. The decision is an economic one, made asset by asset against the cost and consequence of failure.
Run-to-failure vs Preventive maintenance — at a glance
| Dimension | Run-to-failure | Preventive maintenance |
|---|---|---|
| Approach | Operate until it breaks, then fix | Service on a plan to prevent failure |
| Planned cost | None until failure | Ongoing scheduled cost |
| Downtime | Unplanned, at the worst moment | Planned, controllable |
| Best for | Low-consequence, cheap, spare-held items | Critical, costly-to-fail assets |
| Risk | Secondary damage, safety, lost production | Over-servicing, intervention-induced faults |
| Spares strategy | Hold spares, accept the swap | Scheduled parts and labour |
When to choose Run-to-failure
Choose run-to-failure deliberately for low-criticality, low-cost, redundant or easily-swapped assets where a failure causes no safety, environmental or major production impact and a spare is on the shelf — paying to prevent failures that do not matter wastes money better spent on critical equipment.
When to choose Preventive maintenance
Choose preventive maintenance for critical assets whose failure would halt production, threaten safety or cause secondary damage — the planned cost and controllable downtime are far cheaper than an unplanned breakdown at the worst possible moment, and they keep the operation predictable.
Run-to-failure is a decision, not neglect
The crucial distinction is between deliberate and accidental run-to-failure. Choosing to run a cheap, redundant, easily-replaced item to failure — with a spare on the shelf and a plan for the swap — is sound economics; spending scarce maintenance hours preventing failures that cost almost nothing is waste. The danger is the unplanned version, where an asset runs to failure because nobody decided what to do with it, and the failure turns out to cause secondary damage, a safety event or lost production. The strategy is only valid when the consequence has been honestly assessed first.
Common mistakes
Two opposite errors dominate. The first is blanket preventive maintenance — servicing everything on a calendar regardless of consequence, which over-services trivial assets, wastes labour and occasionally introduces faults through unnecessary intervention. The second is undeclared run-to-failure on assets that quietly turn out to be critical, so the first warning is a production stoppage. Both stem from skipping the criticality ranking. The fix is the same in each case: rank assets by the consequence of their failure, then assign run-to-failure, preventive or condition-based maintenance accordingly rather than applying one policy to all.
Verdict
Neither is right for everything. Run-to-failure is the rational, lowest-cost choice for low-consequence assets; preventive maintenance protects the critical ones. A mature programme assigns each asset a strategy based on a criticality ranking, deliberately running unimportant items to failure and protecting the rest.
FAQ
Is run-to-failure ever a good strategy?
Yes, when chosen deliberately for low-consequence, low-cost, redundant or easily-replaced assets with spares held. For such items, preventing failures costs more than the failures themselves, so running them to failure is the rational, lowest-cost approach.
How do I decide which strategy each asset gets?
Use an asset-criticality ranking based on the consequence of failure. High-consequence assets justify preventive or condition-based maintenance; low-consequence, cheap, redundant items can be deliberately run to failure with spares on hand.
What is the danger of unplanned run-to-failure?
An asset failing without a strategy can cause secondary damage, safety or environmental incidents, and production stoppages at the worst possible time. Deliberate run-to-failure assesses these consequences first; accidental run-to-failure does not, which is where it becomes costly.
Related
Asset Criticality · Condition-Based Maintenance (CBM) · Mean Time Between Failures (MTBF)
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