The benefit of naming things to explain them is to obviate the need for jump-to-declaration. Yes, any time I need to know what 5*6 is, I can walk into the other

The benefit of naming things to explain them is to obviate the need for jump-to-declaration. Yes, any time I need to know what 5*6 is, I can walk into the other room and get my calculator -- but if I have that knowledge in my head, I don't need to go look it up. I think it's relatively agreed-upon that single-character variable names are bad, because they don't tell us enough about what the variable holds. So, too, do I feel about the type, when it's not obvious from context. So `age` would be clear enough that it's numeric^1. But what about the other example of `employees`? I would not know what I can do with that without having to jump back to the definition! Naming it `employeesById` tells you what you can do with it. And that seems like a win to me. [1] It might not differentiate between integers and floats, but that feels too nitpicky to me to put in the name.