Tech debt has a clear metaphor: messy code that slows development velocity. Everyone understands it. Engineers can show the cost in sprint velocity metrics.
UX debt doesn't have a good metaphor yet, so it doesn't get prioritised. But it's the same problem: years of expedient design decisions that made sense locally but create a fragmented experience globally.
IndiGo's product had 23 different card variants when I arrived. Three different typefaces used for the same semantic purpose. Seven distinct navigation patterns across product surfaces. Each one had been a rational local decision. Together, they were an incoherent experience.
The cost of this debt: every new designer took 3 weeks to understand the system. Every new feature added friction from inconsistency. User research showed 'the app feels confusing' — not because any one screen was bad, but because the accumulated inconsistency created cognitive friction.
Fixing it took 6 months of parallel work. After: new feature design time dropped 40%. Designer onboarding from 3 weeks to 4 days. UX debt paid off faster than any tech debt I've seen.
The Takeaway
Quantify UX debt in terms engineering and product understand: new feature design time, designer onboarding time, user research confusion scores. Then make the case.