This question already has an answer here:
Lets say i'm a new guy coming to the project, how do I clearly determine if there is a debt on the project? What will show it to me? Lets say a certain amount of TD exists at any project. So the next question is: how to measure it? How to quantify the amount of technical debt? Without resorting to metrics (like code coverage, etc.) how can an "outsider" see if the amount of technical debt is big or not?
A similar question would be: let's say developers are writing "dirty" code which resolves in unconscious technical debt. How would one determine that the amount of the technical debt has suddenly increased on the project? How would it come on sight?