The immediate risk is cost, not an instant outage
A database limit normally creates a licensing and compliance problem before it creates a technical stop. The commercial consequence depends on your contract and renewal timing, so confirm the exact tier rules with Adobe while the operations team audits the database.
Define inactivity with the business
A last-open date alone is not a defensible deletion rule. Include meaningful web, email, form, event, sales and opportunity activity; protect customers, open opportunities, required consent records and legally retained data; then get stakeholder approval.
Separate people, duplicates and operational records
Database composition matters. Identify duplicate people, test and seed records, integration-created records, hard bounces and genuinely inactive prospects. Each group needs different review and recovery rules.
Export, suppress, purge and validate
Create a recoverable export, stop automation from recreating deleted records, execute in controlled batches and validate sync, routing, list counts, reporting and deliverability afterward. One CRM Harmony audit safely purged more than 800,000 inactive contacts and prevented $156,000 in annual costs.