The key skill is to distinguish between harmful repetition, harmless repetition and beneficial repetition.
Say you have two templates (web pages). They are conceptually independent and serve two different business purposes. Yet in terms of their structure/content/whichever, they have about 20% in common.
Somebody obsessed with DRY would now elevate that 20% into some reusable module, after which both templates use it and the repetition is gone. Feels clean.
In reality, you didn't solve a real problem whilst you created a new one. Now individuals/teams cannot independently edit these templates as they need to understand and check the dependency tree. It no longer is simple, there's no piece of mind.
Next, inevitably somebody is going to request changes impacting that 20% and before you know it and after cutting lots of corners, you end up with this freak component that changes output based on some flag.
It's taken me 20 years to come to this conclusion: the negative effects of (too much) DRY (it increases complexity) show up in every single project and make code harder to understand and change. Meanwhile, the negative effects of allowing (some) repetition are mostly theoretical and more often than not a benefit, not a negative.
I mean it. This is coming from an ex-DRY fan boy. The DRY principle makes us eager to connect dots that really aren't connected and shouldn't be connected.
Say you have two templates (web pages). They are conceptually independent and serve two different business purposes. Yet in terms of their structure/content/whichever, they have about 20% in common.
Somebody obsessed with DRY would now elevate that 20% into some reusable module, after which both templates use it and the repetition is gone. Feels clean.
In reality, you didn't solve a real problem whilst you created a new one. Now individuals/teams cannot independently edit these templates as they need to understand and check the dependency tree. It no longer is simple, there's no piece of mind.
Next, inevitably somebody is going to request changes impacting that 20% and before you know it and after cutting lots of corners, you end up with this freak component that changes output based on some flag.
It's taken me 20 years to come to this conclusion: the negative effects of (too much) DRY (it increases complexity) show up in every single project and make code harder to understand and change. Meanwhile, the negative effects of allowing (some) repetition are mostly theoretical and more often than not a benefit, not a negative.
I mean it. This is coming from an ex-DRY fan boy. The DRY principle makes us eager to connect dots that really aren't connected and shouldn't be connected.