The True Costs of Legacy Systems: Technical Debt, Risk, and Exit Strategies

Summary
In this episode Kate Shaw, Senior Product Manager for Data and SLIM at SnapLogic, talks about the hidden and compounding costs of maintaining legacy systems—and practical strategies for modernization. She unpacks how “legacy” is less about age and more about when a system becomes a risk: blocking innovation, consuming excess IT time, and creating opportunity costs. Kate explores technical debt, vendor lock-in, lost context from employee turnover, and the slippery notion of “if it ain’t broke,” especially when data correctness and lineage are unclear. Shee digs into governance, observability, and data quality as foundations for trustworthy analytics and AI, and why exit strategies for system retirement should be planned from day one. The discussion covers composable architectures to avoid monoliths and big-bang migrations, how to bridge valuable systems into AI initiatives without lock-in, and why clear success criteria matter for AI projects. Kate shares lessons from the field on discovery, documentation gaps, parallel run strategies, and using integration as the connective tissue to unlock data for modern, cloud-native and AI-enabled use cases. She closes with guidance on planning migrations, defining measurable outcomes, ensuring lineage and compliance, and building for swap-ability so teams can evolve systems incrementally instead of living with a “bowl of spaghetti.”

Announcements

• Hello and welcome to the Data Engineering Podcast, the show about modern data management
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• Your host is Tobias Macey and today I'm interviewing Kate Shaw about the true costs of maintaining legacy systems

Interview

• Introduction
• How did you get involved in the area of data management?
• What are your crtieria for when a given system or service transitions to being "legacy"?
• In order for any service to survive long enough to become "legacy" it must be serving its purpose and providing value. What are the common factors that prompt teams to deprecate or migrate systems?
• What are the sources of monetary cost related to maintaining legacy systems while they remain operational?
• Beyond monetary cost, economics also have a concept of "opportunity cost". What are some of the ways that manifests in data teams who are maintaining or migrating from legacy systems?
  • How does that loss of productivity impact the broader organization?
• How does the process of migration contribute to issues around data accuracy, reliability, etc. as well as contributing to potential compromises of security and compliance?
• Once a system has been replaced, it needs to be retired. What are some of the costs associated with removing a system from service?
• What are the most interesting, innovative, or unexpected ways that you have seen teams address the costs of legacy systems and their retirement?
• What are the most interesting, unexpected, or challenging lessons that you have learned while working on legacy systems migration?
• When is deprecation/migration the wrong choice?
• How have evolutionary architecture patterns helped to mitigate the costs of system retirement?

Contact Info

• LinkedIn

Parting Question

• From your perspective, what is the biggest gap in the tooling or technology for data management today?

Closing Announcements

• Thank you for listening! Don't forget to check out our other shows. Podcast.__init__ covers the Python language, its community, and the innovative ways it is being used. The AI Engineering Podcast is your guide to the fast-moving world of building AI systems.
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Links

• SnapLogic
• SLIM == SnapLogic Intelligent Modernizer
• Opportunity Cost
• Sunk Cost Fallacy
• Data Governance
• Evolutionary Architecture

The intro and outro music is from The Hug by The Freak Fandango Orchestra / CC BY-SA