>>philbo+he
That's a very interesting question. There are so many things you can look at. How is the documentation? Who are the primary maintainers? How are they funded? What are their motivations? Are the primary maintainers active on Stack Overflow, Reddit, Discord, etc...? How many contributors are there? How does their Github issues page look? What about the Github discussion page? How many maintainers are there total? How many downloads per week on NPM (for JS libraries)? From all of these things - how long do you expect this library to be maintained? And that's just the initial qualification research, nothing about how it will impact the actual code-base.
What did I miss? What's the best answer you've ever heard? How do you evaluate 3rd party dependencies?