Non-production OpenSearch domains often inherit Multi-AZ configurations from production setups without clear justification. This leads to redundant replica shards across AZs, inflating both compute and storage costs. Unless strict uptime or fault tolerance requirements exist, most dev/test workloads do not benefit from Multi-AZ redundancy.

Domains running outdated OpenSearch versions — particularly OpenSearch 1.x — begin to incur AWS Extended Support charges once they fall outside of the standard support period. These charges are persistent and apply even if the domain is inactive or lightly used. Many teams overlook this cost when delaying upgrades or maintaining non-critical environments like dev, test, or staging. In large organizations, outdated versions can silently drive meaningful spend over time, especially across many small or idle domains.