Per-Device Consumable Planning: Budgeting by the Unit
The Two-Layer Model
- Fixed layer: volume-independent consumption (coolant cycles, filter periods, spare amortization).
- Variable layer: scales with sessions (needles, cartridge shots, coupling gel).
The Monthly Budget Sheet
| Item | Formula |
|---|---|
| Variable consumables | Monthly sessions × per-session cost (the per-session math) |
| Fixed amortization | Cycle consumption ÷ months |
| Safety-stock top-up | Refill categories below line (the spares planning) |
| Contingency | 10% float |
Stockout Protection
- Dual suppliers or vendor safety-stock agreements for core items (the clauses).
- Discontinuation watch: monitor the device lifecycle’s later stages (the retirement signals).
FAQ
What share of revenue should consumables take?
Typically 8-15% for energy programs (varies); persistently above 15% — audit per-session usage and shrinkage (the keep cost and service lines separate).
Common Pitfalls and Fixes
- Never reviewing costs: per-session consumable cost drifts with vendor pricing and shrinkage — re-verify quarterly (the cost entry).
- Safety stock becoming expired stock: FIFO and near-expiry flags (the storage standards).
- Consumables not matching volume: monthly reconciliation gaps over 5% demand investigation (requisitions, pilferage, waste).
Minimal Modeling Data
- Six months of session volumes.
- Per-program consumable lists.
- Replenishment lead times per item.