What about something that takes 10 lines, repeated 3 times across a codebase; versus a single implementation that takes 100 lines but is only used once? This a

What about something that takes 10 lines, repeated 3 times across a codebase; versus a single implementation that takes 100 lines but is only used once? This appears to be the breaking point in web dev. I wish someone could properly articulate why the first option is so bad, without invoking DRY (Don’t Repeat Yourself) or some bastardization of SOLID Principles.