Each team commits ten percent of its sprint capacity to debt-paydown work. It's not optional and it's not the first thing cut when the roadmap tightens.
We keep a written register of significant debt items, scored by both the cost of carrying it and the cost of paying it down. Items get pulled into normal sprint work when the math says now.
We also do a quarterly health check on each major service. If the health is yellow, the next sprint is a paydown sprint.
