Lightning Web Components (LWC) and Flows are all powerful tools in the Salesforce ecosystem, each with its strengths and use cases. Let’s compare them to understand when you might choose one over the others:

Advantages of using Apex:

1. Flexibility: Apex allows for complex logic and data manipulation that may not be possible with declarative tools.
2. Performance: Apex can be more efficient for large data volumes or complex operations.
3. Integration: Easier to integrate with external systems and APIs.
4. Batch processing: Apex can handle large data sets through batch Apex.
5. Reusability: Create utility classes and methods that can be used across the org.
6. Triggers: Apex is required to create database triggers.
7. Test coverage: Allows for comprehensive unit testing.

Advantages of using Lightning Web Components (LWC):

1. Modern UI: Create responsive and interactive user interfaces.
2. Performance: LWCs are generally faster than Aura components.
3. Reusability: Components can be easily reused across different parts of the application.
4. Standards-based: Uses modern web standards, making it easier for web developers to work with.
5. Better developer experience: Improved tooling and debugging capabilities.
6. Modularity: It is easier to maintain and update specific parts of the UI.

Advantages of using Flows:

1. No-code/low-code: Business users can create and maintain flows without extensive programming knowledge.
2. Visual design: It is easier to understand and design process logic visually.
3. Rapid development: Quicker to build and deploy for many use cases.
4. Declarative: Changes can be made quickly without code deployments.
5. Automation: Great for automating business processes.
6. Integration with other declarative tools: Works well with other Salesforce point-and-click tools.

When to choose Apex or LWC over Flow:

1. Complex logic: When the business logic is too complex for Flow’s capabilities.
2. Performance needs: For high-volume data processing or when optimal performance is crucial.
3. Custom UI requirements: When you need highly customized, interactive user interfaces.
4. Developer expertise: When you have experienced developers who can leverage the full power of code.
5. Reusable code: When you want to create a library of reusable functions.
6. External system integration: For complex integrations with external systems.

However, it’s worth noting that these tools are not mutually exclusive. You might combine Apex, LWC, and Flows in many Salesforce projects to achieve the best results. For instance, you might use a Flow for the overall business process, call an Apex method for complex calculations within that Flow, and use an LWC to display the results in a user-friendly manner.

The choice often depends on your project’s specific requirements, your team’s skills, and the long-term maintenance considerations. Generally, it’s a good practice to use declarative tools like Flows for easier maintenance and to reserve Apex and LWC for scenarios where their additional capabilities are genuinely needed.