Reserved instances versus savings plans

Overview

Azure Reservations and AWS Savings Plans / Reserved Instances cut spend in exchange for a term commitment. The MSP’s job is to match commitment to stable baselines, not to speculative growth.

Decision matrix

• High stability (domain controllers, steady DB): reservations / RIs on matching SKUs.
• Mixed or changing shapes: compute savings plans or flexible RI where available.
• Spiky batch: avoid locking; use spot or pay-as-you-go with autoscaling caps.

Process

1. Export cost and utilization for the last 90 days; strip one-off projects.
2. Model breakeven vs on-demand with finance (cash vs amortization).
3. Purchase in the payer or billing profile with correct scope (single subscription vs shared).
4. Set calendar renewal and utilization review at 60 days before term end.

Risk note

Refunds/exchanges have limits—document who signs commitments and how mergers affect usage.