[MatekCopatek]

I wouldn't say that they are always mutually exclusive. I think there is a variable ratio between advantages gained by 1. and disadvantages caused by 2.

In other words, at first, reducing repetition will net nearly no negative results - you just recognise different areas that do very similar things and write a common functionality. The most basic example would be programming languages providing standard libraries, even though everything could be done with regular operations. At this point, abstractions are even simpler to use than implementing things yourself.

Problems start to arise once you hit a certain point beyond which your abstractions become harder to use and maintain than simply writing things multiple times. This is where you should stop abstracting/modularising things away (assuming that the reason is purely overengineering, not bad engineering).