What are the pros and cons of a custom UI kit?

Pros of a custom UI kit:

• Full adaptation to the project's needs and corporate style.
• Ability to optimize for specific tasks and performance.
• Control over the quality and behavior of components.
• Absence of unnecessary functionality, which reduces the bundle size.

Cons of a custom UI kit:

• High time and resource costs for development and maintenance.
• Risk of bugs and shortcomings without a broad user base.
• Requires a team with experience for creation and support.
• Fewer ready-made solutions and documentation compared to popular libraries.

Thus, a custom UI kit is justified if the project is unique and requires precise tuning; otherwise, it is better to use proven third-party solutions.