The deadline that doesn't email you

A proposed rule on device classification posts with a ninety-day comment window. Three weeks later, a draft guidance on a related question posts with sixty. A narrower draft guidance, the same month, gives interested parties ten days. Nothing on the Federal Register page tells you this variation exists — usually you notice it by having missed one.

There is no default

It is tempting to memorise “comment periods are sixty days” the way you memorise a CFR citation, and it is wrong often enough to be dangerous. Comment windows are set case by case, per document, by the office issuing it. FDA’s own guidance on the docket and comment process describes how to participate without promising a standard length, and the published record shows why a promise would be false: comment periods on FDA device-related documents run anywhere from about ten days to nine months, depending on what is being proposed and how urgent the agency judged it. Memorising a typical number is exactly the habit a monitoring practice is supposed to replace.

The one place a number actually exists

Draft guidance is the exception, and it is worth knowing precisely why. FDA’s Good Guidance Practices regulation — 21 CFR 10.115 — governs how the agency develops and issues guidance, and FDA’s own background on the rule states that a sixty-to-ninety-day comment period is generally appropriate for most Level 1 (significant) draft guidance. That is a real, citable policy position, not folklore — and it is exactly why it should not be generalised to every other document type, where no equivalent commitment exists. A draft guidance is a comment opportunity FDA has committed, in writing, to holding open for a predictable window. A proposed rule is not making you that promise.

The field that actually answers the question

Every Federal Register document carries a comments_close_on value in the agency’s own structured record — not a convention, a field, populated per document, present in the API the Federal Register publishes for exactly this purpose. Comments are filed against a docket — a unique docket ID minted per rulemaking, through regulations.gov — and both the docket ID and the closing date exist in the record from the day the document posts. The discipline is simple to state and easy to skip under volume: read the field, every time, for every document that touches your CFR parts. Do not infer the date from the document type. The one time the inference is wrong is the one that costs you the window.

A monitoring habit that memorises typical values is a habit waiting for the atypical one.

The weekly habit that catches it

FDA publishes to the Federal Register on essentially every day it is open for business, which means a document relevant to your CFR parts can post on a Tuesday and close before a monthly review ever looks at it. The operating cadence that works for a small RA team is a standing weekly pass: pull the current week’s device-relevant documents, and for each one, log three things on a running board — the docket ID, the comments_close_on date, and a one-line note on whether it touches your portfolio. Then review the board itself weekly, sorted by closing date, not by when the item was logged. A window that opened eight weeks ago and closes next Friday is more urgent than one that opened yesterday and closes in the spring, and a board sorted by arrival order hides exactly that.

Whether to comment at all, and what to say, is a judgment call this post is not making for you — it depends on your product, your competitive position, and your counsel’s read of the docket. This is regulatory intelligence about where the deadline lives, never regulatory advice about what to file against it. What the habit buys you is the part that is not a judgment call: knowing the window is open, and how many days are left in it, before it closes without you.

FDA Radar runs this same field through its own pipeline — every Federal Register item we ingest carries its own comments_close_on date and docket IDs as structured facts, not something a reader has to go find. Deciding whether a given docket is worth your comment is still yours. Knowing it exists, and when it closes, no longer has to be.