The term technical debt encompasses a broad array of issues, such as planned debt, naturally depreciating code, and architectural changes.
All software teams will have to deal with technical debt eventually. Often this happens because we have already let things get pretty bad, and now we have to dig ourselves out. There is a variety of technical debt that can accumulate within a system, and no single solution can be applied universally, but by identifying the source of certain types of debt and proactively planning to address them, we can stop interest damage from accruing.
Planned debt: Trading quality for speed
The first, purest sense of the debt metaphor is accepting a future burden in exchange for immediate benefit.