Nothing about D.D.C. practice is secret; it's just distributed across local rules, standing orders, and clerk's-office habits that regulars absorb and visitors discover at midnight. A field guide.
The service version: local counsel who file here weekly carry this manual as reflex — which is what the engagement buys beyond the signature: filings that land right the first time, on dockets watched by someone in the right timezone.
By chambers, not by district — some judges want them, some forbid them; the standing order rules. Assume nothing across judges, even in the same case after reassignment.
Usually a strike-and-refile with a docket entry announcing it — cheap in law, expensive in first impressions before the judge who'll decide your merits.
Substituting or adding local counsel mid-stream is routine and unremarkable — cleaner than another round of docket corrections.