Vibe Coding Works Great, Until It Hits the Three-Month Wall

Vibe coding and spec-driven development are getting compared constantly right now. Both have real tradeoffs, and the data on each is more concrete than either side's marketing usually admits. The case for vibe coding: research cited in the comparison shows developers using AI code generation completing tasks 55% faster on average. For prototypes, solo projects, and internal tools, that speed is the entire point. The case against it as a default: GitClear's analysis of 211 million lines of code found refactoring activity dropped roughly 60% between 2021 and 2024, while copy-paste instances rose about 48% — and 2024 was the first year copy-pasted lines outnumbered refactored lines. Code duplication has been measured increasing up to 8x in AI-assisted codebases. Then there's the three-month wall: projects run fast early, then technical debt, integration friction, and requirements drift from unstructured chat history all compound at once, and delivery stalls. What's actually emerging in practice isn't "pick one forever" — it's sequencing. Explore with vibe coding, then formalize into a version-controlled spec before production. #VibeCoding #SoftwareEngineering #AICoding #DeveloperTools #Programming