Instead of technologies, I would put having the basics.
Some people get far too used to working with one framework that they blur what is framework and what is language.
But I have to disagree about the "how much time they take".
I mean, sure, if you compare the same task, yes, probably it will go like that. But having a team means that a senior don't have to make something a junior or a mid can do, and can, instead, do things that the others can't or don't even know how to start. (like performance, scalabity, security...) Altough, yes, they still need to "take care" of others.
True, but a senior would not be limited to performance, scalability and security. They do development tasks just like the other team members.
In my last project, I had 1 junior with me. What I did was I usually gave him the easy tasks and took the harder tasks on me. Even the easy tasks would take a long time with him and he would ask me 1000 questions until I finally give him the solution.
Instead of technologies, I would put having the basics.
Some people get far too used to working with one framework that they blur what is framework and what is language.
But I have to disagree about the "how much time they take".
I mean, sure, if you compare the same task, yes, probably it will go like that. But having a team means that a senior don't have to make something a junior or a mid can do, and can, instead, do things that the others can't or don't even know how to start. (like performance, scalabity, security...) Altough, yes, they still need to "take care" of others.
True, but a senior would not be limited to performance, scalability and security. They do development tasks just like the other team members.
In my last project, I had 1 junior with me. What I did was I usually gave him the easy tasks and took the harder tasks on me. Even the easy tasks would take a long time with him and he would ask me 1000 questions until I finally give him the solution.
Sounds like you are a bad mentor