Technical Debt is a great metaphor, but it is just a metaphor. I've seen people try to quantify it and it just seems ridiculous. They try to take some measure of badness and then multiply it by the number of person hours it takes to correct it.<p>Much of what counts as badness in code never gets in the way until you have to understand or touch a particular area of code. The impact depends upon change cases.
Technical debt isn't drastic enough to get people's attention - in particular management. I prefer to talk about the technical credit card - I find that it gets across the point that the debt needs to be addressed.