A stack becomes maintainable when every tool has a reason to exist, a clear input, and an observable handoff.
Map the recurring workflow
Start from repeated work: research, drafting, review, analysis, support, coding, or operations. Mark where time is lost or quality varies.
Assign one owner per job
Do not add two products that solve the same step unless the redundancy has a deliberate reason such as risk isolation or a materially different context.
Keep review close to the consequence
The more irreversible, public, expensive, or sensitive the action, the stronger the review and authorization boundary should be.
Measure replacement friction
Prefer portable prompts, exports, documented workflows, and standard integrations where practical. A useful stack should be able to evolve without a total rebuild.