I think I interpret "Only learn something new when forced" is more like you should prioritize what to learn to do a task. Learning new things to learn new thing

I think I interpret "Only learn something new when forced" is more like you should prioritize what to learn to do a task. Learning new things to learn new things is different than having a concrete project that emphasizes that you should learn one new thing. Learning the newest system of the week isn't really going to help you as much as a tried and true system that is well maintained and proven to work. The second part about linking to other software is valid. What if the thing you are linking to is not going to be maintained? What if the thing you are linking to has a security issue? Now you are probably going to have to either link to something else or replicate the functionality. By only linking to things that are essentially hard to replicate instead of blindly linking to anything else. In the above examples it is more of striking a balance instead of mere absolutes.