A big part of that branching out in my opinion is expanding vistas in areas unrelated to engineering, like reading good literature, creating or appreciating art, and travel.
When I try new programming methodologies, ideas, etc, I often notice a distinct change in how I program and how I think about programming.
When I try new life choices (emmigrating to the third world, reading good literature, etc) I grow as a person, but I really can't think of how it's affected my programming.
Growing as a person I think does help in those aspects.
* design is everywhere
* having a sense of taste is vital to anyone who makes things
* end users are severely affected by every design decision you make
Most design people aren't happy about that level of scrutiny, but that is something they should do, as it will improve their craft.
-a c# programmer learning python -a sql expert learning cassandra
etc?