When you should definitely maintain a component library
The current complexity of front-end development prevents even code-savvy designers to work directly on the product design. There’s also a good chance that your interface has been designed with a design tool like Figma. This creates a gap between the design and the implementation of that design.
A component (and pattern) library can be seen as the middle ground between design and development. It’s an environment that’s easier to learn for a designer and a good place for both profiles to meet each other and discuss. You share ownership so you can work together towards a better design and implementation.
No matter the size of your team and the phase of your product, a component library is something to look into. It’s a small effort to document components as you develop them. It will definitely speed up development along the line because you can centralise visual changes, accessibility improvements and bug fixes.
Eventually, it will give you a solid base to create a full design system.