I've worked on some big, mature code bases, and I've always appreciated it when other people believe in YAGNI. It tends to result in relatively simple code with

I've worked on some big, mature code bases, and I've always appreciated it when other people believe in YAGNI. It tends to result in relatively simple code with just enough complications to support the features which actually exist. In theory, it would be nice if the code included appropriate hooks and abstractions. But in practice, it's often quite hard to guess where those hooks should be, and which aspects of the code should be abstracted. And since the abstractions are based on hypothetical designs, they're very often useless. Basically, I'd rather maintain over-simplistic code that implements a few features well than code that has been prematurely generalized to support half a dozen features which don't exist yet. All too often, the generalizations are wrong, or simply get in the way of other features I'm trying to add. Unfortunately, YAGNI is one of those rules that requires common sense to apply well. It works best as a sanity check for an already-experienced programmer: "Really? Do I actually need a whole new set of abstract interfaces here? Or can it wait?" If a programmer is totally lacking in taste and judgement, YAGNI won't save them by itself.