Summary

Pattern Comparison

Pattern	When to Apply	Strengths	Caveats	Common Use Cases
Factory Method	When choosing implementations dynamically	Great extensibility	Requires subclass-based design	Flexible creation of simple objects
Abstract Factory	When generating related objects as a group	Enables consistent environment setup	Slightly more complex structure	UI configuration, environment switching
Builder	When building objects in multiple steps	Flexible and clear construction	Overkill for simple objects	Multi-stage initialization scenarios
Singleton	When sharing a single instance globally	Shared state, high reusability	Can hinder testing and dependency injection	Logger, configuration, cache

Choosing the Right Pattern

• Frequent use of new scattered across the code is a sign of design issues
• Centralizing instantiation improves testability, extensibility, and maintainability
• Choose the pattern based on object complexity and relationships among instances

Team Discussion Snippets

• “There’s too much new scattered around—let’s manage this with a Factory.”
• “Since the logger is shared, we might want to make it a Singleton.”
• “This object has a complex set of properties—Builder could make it clearer.”
• “If we need to switch dependencies per environment, Abstract Factory might fit.”