The other side to it is that you'll rarely be writing completely new code from scratch in the majority of development positions (especially as a new developer).

The other side to it is that you'll rarely be writing completely new code from scratch in the majority of development positions (especially as a new developer). Being able to dive into someone else's code, think about it, an add something to it, is probably more important on a day-to-day basis than being able to create something from scratch.