How to Explain Technical Debt to Non-Tech People

I find technical debt easier to explain through a change we're struggling to make. This form takes longer to update because the validation is duplicated in three places; here is what consolidating it would let us do.

That gives people something concrete to weigh against other work. Not every untidy corner needs fixing immediately. I want the discussion to be about the cost we're actually paying, rather than whether the code meets an abstract standard of cleanliness.