All 5 recommendations
Est. prices as of Mar 11, 2026
#1 · Robert C. Martin · Most Overhyped
Single Responsibility Principle (SRP)
Free (in theory)
Do one thing and do it well—if you can figure out what 'one thing' means
- âś“ Theoretically reduces complexity and improves testability
- âś“ Makes code easier to understand at first glance
- âś“ Encourages modular architecture
- âś— Developers can't agree on what constitutes a single responsibility, creating analysis paralysis
#2 · Bertrand Meyer · Hidden Gem
Open/Closed Principle (OCP)
$0
Open for extension, closed for modification—good luck with that legacy codebase
- âś“ Reduces risk of breaking existing code when adding features
- âś“ Encourages planning and abstraction upfront
- âś“ Scales well in mature systems
- âś— Requires expensive upfront architecture decisions that often prove wrong; most teams just modify existing code instead
#3 · Barbara Liskov
Liskov Substitution Principle (LSP)
$0
Subclasses should be substitutable—until your Square inherits from Rectangle
- âś“ Prevents runtime polymorphism bugs
- âś“ Enforces correct inheritance hierarchies
- âś“ Makes code more predictable
- âś— Violated constantly when developers use inheritance for code reuse instead of behavioral contracts; the Square/Rectangle problem proves even theory has edge cases
#4 · Robert C. Martin
Interface Segregation Principle (ISP)
$0
Many client-specific interfaces beat one god interface—except when they don't
- âś“ Reduces coupling between components
- âś“ Clients only depend on methods they actually use
- âś“ Easier to mock in unit tests
- âś— Creates interface bloat if taken too literally; teams oscillate between megainterfaces and microinterfaces depending on what fails code review that week
#5 · Robert C. Martin · Best Value
Dependency Inversion Principle (DIP)
$0
Depend on abstractions, not concretions—now go debug why your DI container is broken
- âś“ Enables true testability through dependency injection
- âś“ Reduces tight coupling between modules
- âś“ Industry standard for enterprise architecture
- âś— DI container configuration becomes a nightmare; Spring and Guice configs often obscure dependencies rather than clarify them, and 'magic' beans fail in production