Continuous review or fixed review cycles: how replenishment triggers
Every replenishment policy answers two questions: when to order and how much. One approach watches stock continuously and acts when it falls to a defined level; the other looks at fixed intervals and tops up to a target. The choice affects how much buffer you carry, how orders consolidate across items and how much your systems must do unattended.
Comparison criteria
Criteria are stated explicitly and neither option is declared a winner: which one fits depends on the constraint that binds hardest in your operation.
| Criterion | Continuous review with a reorder point | Periodic review with a top-up target |
|---|---|---|
| Trigger | Stock reaching a defined level, whenever that happens. | The arrival of the review date, whatever the stock position. |
| Data and system demands | Requires stock positions that are accurate continuously, since the trigger can occur at any moment. | Requires accuracy only at the review, which suits operations that count or reconcile on a cycle. |
| Buffer needed | Covers variability during the supply lead time alone. | Covers the lead time plus the interval until the next review, so more buffer is required for the same protection. |
| Order pattern | Orders appear at irregular moments, item by item, which fragments purchasing. | Orders group naturally at the review, which suits consolidating across items for a full vehicle or a minimum value. |
| Response to a demand spike | Reacts as soon as the level is breached. | Waits for the review, which is why the extra buffer exists. |
| Administrative rhythm | Continuous, which fits automated ordering and unattended systems. | Predictable and batched, which fits teams who plan purchasing on set days. |
| Supplier fit | Works with suppliers who accept orders at any time and deliver on short notice. | Works with suppliers who deliver on fixed days or expect a consolidated order. |
Choose Continuous review with a reorder point when
- Stock records are accurate in real time and the system can act on them without human intervention
- The item is critical enough that waiting for a review date would risk running out
- Suppliers accept orders at any time without a minimum drop size that forces consolidation
- Demand is irregular, so a fixed cycle would either order too early or react too late
Choose Periodic review with a top-up target when
- Suppliers deliver on set days or require a consolidated order to make a delivery worthwhile
- Stock accuracy is verified on a cycle rather than maintained continuously
- Ordering across many items together produces transport or purchasing savings
- Demand is stable enough that the extra buffer costs less than the coordination it saves
The buffer difference is structural
A trigger-based policy must protect against variability during the supply lead time. A cycle-based policy must protect for that period plus the wait until the next review, because nothing will be ordered in between. For the same service level, the cycle-based approach therefore carries more stock, and the gap widens as the interval lengthens. That extra stock is the price paid for coordination and simplicity. Whether it is worth paying depends on the value and volume of the item, which is why many operations apply different policies to different parts of the range rather than one policy to everything.
Segment the range and let the item choose
A practical design applies continuous review to high-value or critical lines, where the buffer saving is worth the system discipline, and a cycle-based approach to the long tail, where grouping orders matters more than a few units of extra stock. Segmenting by value and criticality is straightforward and stable. What causes trouble is applying an inherited policy across a range where a few lines dominate the value and the rest dominate the line count, since neither group is well served by a compromise.
Parameters decay quietly
Whichever approach is used, the parameters were set against a demand pattern and a lead time that will change. Trigger levels and top-up targets built years ago quietly become wrong, producing either shortages nobody can explain or stock nobody remembers ordering. Set a recalculation rhythm and hold to it, and review whenever a supplier's lead time changes or a product's demand shifts materially. Most complaints about a replenishment policy turn out to be complaints about parameters nobody had revisited.
Frequently asked questions
- Can both policies run in the same operation?
- Yes, and most operations should. The policy belongs to the item rather than to the business, and applying different rules by value and criticality usually produces less stock and better availability than a single approach.
- What breaks a trigger-based policy most often?
- Inaccurate stock records. The trigger fires against what the system believes, so an unrecorded movement or a miscount either delays an order or launches one that was not needed. Accuracy discipline is a precondition rather than an improvement.
- How is the review interval chosen?
- Usually by what the supply and transport arrangements support: delivery days, minimum order requirements and how orders consolidate. Shorter intervals reduce the buffer but add coordination, so the interval should follow the operating rhythm rather than a theoretical optimum.
Data limitations
- Logistics figures are operator-supplied inputs, not market data. GeoBusinessIQ holds no freight rates, transit times, capacity, or throughput data and does not estimate them — every result reflects only the figures you enter.
Explore the graph
Related logistics topics
Sources
- OECD — OECD — economic and tax statistics (accessed ; reviewed )Covers: Comparable corporate tax, statutory rate, and economic indicators across member and partner economies.Does not cover: Effective tax rates, deductions and incentives, local surtaxes, and personal residency rules.Why it matters: Used as a cross-country baseline to sanity-check rates against primary tax-authority figures.Review cadence: Annual, plus on major statutory changes.
- World Bank — World Bank — Trade (accessed )Covers: Trade and logistics performance research, trade facilitation and supply-chain development analysis.Does not cover: Live freight pricing, carrier schedules, or company-level logistics data.Why it matters: Multilateral development institution publishing comparative research on trade logistics; used for structural comparison, not for point-in-time operational figures.Review cadence: as published
Educational and operational information only — not legal, customs, tax, insurance, or financial advice. Requirements vary by jurisdiction, commodity, and contract; confirm with the relevant authority or a qualified adviser before acting.
Last updated: