AWS Lambda allows deployment and scaling of individual functions, but engineers often think in terms of services. A service is a cohesive group of functions deployed together as a unit through CloudFormation, making it easier to reason about large systems and maintain autonomy among teams. Deployment frameworks like Serverless or AWS SAM help configure and deploy functions in terms of services. The question of how to organize functions into repositories is crucial, with two common approaches: monorepo (everything in one repo) and one per service (each service gets its own repo). Monorepos are productive for small teams but can become unfeasible as the organization grows due to coherence penalty issues. One repo per service avoids these challenges but incurs overhead from setting up new repos. The choice between monorepo and one repo per service depends on the organization's growth stage, velocity requirements, and existing codebase. For startups with high velocity needs, a monorepo might be suitable, while enterprises should consider sticking to their established approach or splitting the monorepo if necessary.