Angular Signals enables more granular change detection by updating only dependent components, eliminates Zone.js overhead, and greatly reduces RxJS subscription boilerplate. With lazy evaluation and memoization, CPU performance improves (measured gains of 20-40%), and code maintenance becomes simpler with a native, easy-to-understand API.

We recommend starting by identifying local state or simple forms and progressively replacing BehaviorSubjects with writable signals. Exposing readonly signals in services minimizes the impact on the presentation layer. Measuring gains at every step, maintaining unit tests, and keeping hybrid RxJS-Signals modules ensure a controlled transition without functional disruptions.

Common pitfalls include overly dense dependency graphs, misuse of computed signals for heavy, non-memoized computations, or directly mutating shared data without readonly signals. To mitigate risks, clearly structure writable, computed, and readonly signals, maintain a comprehensive test suite, and validate the impact of change detection adjustments on the user experience.

Measuring the impact involves tracking KPIs like average render time, CPU usage, and change detection cycle frequency. Use performance profiling (Chrome DevTools) and end-to-end benchmarks (Lighthouse, Sitespeed) before and after migration. Gains are typically observed on performance-intensive screens, with a notable reduction in unnecessary recalculations.

Writable signals define the source state - mutable and localized. Computed signals produce derived data, recalculating only when their dependencies change. Readonly signals serve as an observation interface without allowing external mutations. This separation promotes a modular architecture, ensures data integrity, and simplifies unit testing.

A hybrid approach is preferred when the application handles complex multi-event orchestration (WebSockets, concurrent streams) where RxJS is still more suitable. RxJS subscriptions can feed writable signals, combining orchestration power with the reactive simplicity of Signals. This progressive strategy lets you migrate modules one by one without immediately impacting the entire project.

For forms, each field becomes a writable signal, while computed signals calculate overall validity, error messages, or submission state. This approach partially replaces FormGroups for simple scenarios, offering declarative logic that's easy to test. Isolating validations in computed signals improves readability and maintainability.

Evaluate project size and complexity, team expertise, and needs for fine-grained reactivity. For applications requiring targeted updates, scalable maintenance, and reduced boilerplate, Angular Signals are a suitable choice. Native integration, no external dependencies, and modularity also facilitate scaling.