Preventive maintenance costs should be planned against asset criticality and the consequences of failure. Servicing everything as often as possible wastes labor and parts; waiting for every asset to fail can create unsafe work, emergency premiums, lost production and dissatisfied customers. The right policy balances risk, evidence and lifecycle economics.
Build an asset register
Record asset ID, location, owner, manufacturer, model, age, warranty, expected life, service requirements, parts, failure history, downtime and replacement lead time. Link work orders and invoices to the asset. Without consistent history, maintenance decisions become anecdotal.
Rank criticality before setting intervals
| Factor | Question | Higher-risk signal |
|---|---|---|
| Safety/compliance | Could failure harm people or violate a rule? | Severe consequence |
| Operations | Does the asset stop a bottleneck process? | No practical workaround |
| Quality | Can deterioration create defects? | Failure is hard to detect |
| Recovery | How quickly can service resume? | Long parts or vendor lead time |
Follow applicable law, safety rules and manufacturer instructions. Condition-based or predictive maintenance may improve timing when sensor data is reliable; it does not eliminate required inspections.
Capture the full cost of failure
Add technician time, parts, contractor premium, shipping, cleanup, scrap, lost contribution margin, customer penalties, restart and investigation. Also record planned-maintenance labor, consumables and scheduled downtime.
Expected failure cost = probability of failure × consequence if failure occurs. Both inputs are estimates, so show a range and document the evidence. Low-frequency safety or compliance risks may require controls regardless of the expected-dollar result.
Choose the maintenance strategy
- Run to failure: suitable only when consequences are low and replacement is easy.
- Time or usage based: appropriate when service intervals are established.
- Condition based: act on inspected or monitored deterioration.
- Redesign or replace: use when recurring failure remains unacceptable.
Do not perform unnecessary intrusive maintenance if it introduces new failure risk. Review the task and interval using actual history.
Measure program effectiveness
Track planned versus unplanned work, schedule compliance, repeat failures, downtime, maintenance cost by asset, parts stockouts and mean time between failures. Interpret metrics together: high schedule compliance is not success if failures and costs keep rising.
Integrate findings with the technology damage prevention checklist for power, environment, software and recovery risks.
Frequently asked questions
Is preventive maintenance always cheaper?
No. Overservicing low-risk assets can cost more than repair. Compare strategies using failure consequences, evidence, required intervals and lifecycle cost.
How should spare parts be prioritized?
Consider asset criticality, failure rate, supplier lead time, substitutability, storage life and carrying cost. Critical does not automatically mean keeping unlimited stock.
When should an asset be replaced?
Review safety, support, reliability, energy, maintenance trend, downtime, capacity and replacement lead time. Compare the risk-adjusted cost of keeping versus replacing it.
Sources reviewed
- OSHA safety and health programs
- U.S. Department of Energy: O&M best practices
- U.S. GAO Cost Estimating and Assessment Guide
Last reviewed: August 15, 2026.