What is Technical Debt?
Technical debt is the accumulated future cost of past shortcuts — quick hacks, skipped tests, outdated dependencies, design decisions outlived by reality. Like financial debt it has principal (the cleanup) and interest (everything gets slower until you pay). Some debt is strategic — shipped fast on purpose, with eyes open; most is accidental and compounding.
Mature teams make it visible (tracked, estimated, on the board) and service it continuously — a slice of every sprint — because the alternative, the "big refactor someday," is a loan payment nobody ever schedules.
Worked example
A checkout service hard-coded one tax regime in 2022 to hit a launch. Interest since: every new market takes three weeks instead of two days. The team finally pays the principal — a two-sprint tax-engine extraction — and the next market launches in a day and a half. The CFO understands it instantly when framed as debt: we borrowed speed in 2022, and we've been paying 40% APR ever since.