I would agree that it doesn’t have a fixed interest rate. But you might say it has a variable interest rate. The trick is to accurately gauge the true interest

I would agree that it doesn’t have a fixed interest rate. But you might say it has a variable interest rate. The trick is to accurately gauge the true interest rate and only work on the technical debt that costs you over time. The real tricky technical debt is the one that has a small cost, but accrues frequently. At any given time it is easy to tell yourself “this doesn’t cost much and would take me 10 times as long to rewrite than to just make this quick fix”. But if you (or more likely other people) have to keep paying that cost dozens, hundreds, or even thousands of times in the future, then the right decision is to schedule some time to take care of the debt.