The React component lifecycle consists of various phases that a component undergoes from its creation to its destruction. Understanding this lifecycle is crucial for optimizing performance and managing side effects effectively. The lifecycle can be divided into three main phases: Mounting, Updating, and Unmounting. During the mounting phase, components are initialized and inserted into the DOM, allowing developers to set up initial state and make API calls. The updating phase occurs when a component receives new props or state, triggering re-renders of the component. Finally, the unmounting phase is where cleanup activities are performed, such as cancelling API requests or removing event listeners.

Each phase of the React component lifecycle provides specific lifecycle methods, such as componentDidMount(), componentDidUpdate(), and componentWillUnmount(), which allow developers to execute code at critical points of a component's existence. For example, componentDidMount() is often used for data fetching and DOM manipulations after the component has been rendered, while componentWillUnmount() is essential for cleaning up resources to prevent memory leaks. By effectively leveraging these lifecycle methods, developers can create more efficient and maintainable React applications, leading to improved user experiences.

Building reusable React components can significantly enhance your development process, allowing for more maintainable and scalable code. Here are 10 best practices to keep in mind when creating these components:

1. **Design for Reusability**: Ensure that components are designed to be flexible and adaptable. Use props to pass data and configurations rather than hardcoding values, promoting reusability across different parts of your application.
2. **Single Responsibility Principle**: Each component should have a single job. This makes components easier to manage, test, and reuse. Aim for components that perform a distinct function or represent a singular piece of UI.

When developing with React, one of the common mistakes developers make is failing to properly manage component state. Not taking advantage of the useState and useEffect hooks can lead to inefficient rendering and unnecessary re-renders. To mitigate this, always ensure that stateful logic is managed correctly by encapsulating related state in a single component and lifting state up appropriately when needed. This practice not only enhances performance but also improves the readability of your code.

Another prevalent mistake is neglecting to create reusable components. Writing components that are overly specific or tightly coupled to specific use cases can lead to code duplication and maintenance challenges. Instead, focus on creating components that are flexible and reusable by passing props effectively. Employ techniques such as prop drilling or the Context API to share state among components without excessive duplication, which can later simplify your application as it scales.