A few scenarios I can think of are: 1) If it doesn't work or works poorly. 2) If it is trivial to implement. 3) Licensing problems. 4) If the implementation

A few scenarios I can think of are: 1) If it doesn't work or works poorly. 2) If it is trivial to implement. 3) Licensing problems. 4) If the implementation is overly complicated. 5) The (framework) vendor have a habit of updating and breaking your code. This happens a lot with the Angular team. There is nothing like the annoyance of an Angular update and they have broken some feature you are using and you have to update code that was working absolutely fine. Since then I have avoided Angular entirely. Things I am less strict on: 1) The project is EOL. It may work perfectly fine. This happens to open-source software as well. Typically this means there is a better alternative out there. 2) Awkward syntax / api. You can normally just wrap this. 3) Maintainers are difficult to work with or don't fix bugs.