Fellow list reader, Pieter-Jan Smets, replied to my message about tech debt weeks with a disaster story of his own. Shared with permission, lightly edited for clarity:

I liked your mail on “Tech Debt Week”. I agree that in most cases, planning such a week is an anti-pattern. We had a 6-week long “Tech Debt Week” last summer, which led to huge issues.

Our devs don’t work with short-lived branches. What ended up happening: everyone was working on huge parallel refactorings in their own branch. The devs thought all was fine, because everyone was merging master in their own branch daily, to prevent merge conflicts.

Of course, everyone only merged their massive branches to master at the end of those 6 weeks, leading to massive merge conflicts, lots of headaches and the necessary bugs afterwards.

So I get what you were talking about there.