How does the federal mask mandate end?

Question

I had thought that President Biden was only going to issue a mask mandate that lasted 100 days,

President-elect Joe Biden, who plans to make the coronavirus pandemic his top priority, will begin his presidency by asking Americans to wear masks for 100 days and requiring their use on federal property.
His first executive order, the "100 Days Masking Challenge," will symbolize the administration's sharp turn from the Trump era by emphasizing recommendations by public health experts. A president cannot tell states or cities what to do, but a federal mandate will affect federal offices and federal lands and will urge states to do the same.

https://www.cnn.com/2021/01/20/health/biden-first-day-health-executive/index.html

but in reading the executive order, there appears to be no sunset, and no limitation and if it isn't rescinded the expectation is that we'll always be expected to wear masks on federal lands and in federal buildings.

https://www.whitehouse.gov/briefing-room/presidential-actions/2021/01/20/executive-order-protecting-the-federal-workforce-and-requiring-mask-wearing/

So, from a legal standpoint, does this executive order necessarily need to be rescinded, does it go away when the CDC no longer recommends masking or does it remain perpetually?

Answer 1

Section 2 (a) of the order says:

The heads of executive departments and agencies (agencies) shall immediately take action, as appropriate and consistent with applicable law, to require compliance with CDC guidelines with respect to wearing masks, maintaining physical distance, and other public health measures by: on-duty or on-site Federal employees; on-site Federal contractors; and all persons in Federal buildings or on Federal lands. (emphasis added)

It would seem that if, in future, the CDC changes its guidelines to indicate that mask wearing is no longer needed (presumably in the wake of a large decline in cases) the order would mean compliance with such revised guidelines, and thus reduced or eliminated mask wearing, when and if that is advised.

The order does not contain any dated sunset or reevaluation provision. But the President can at any time revise or rescind this or any other Executive Order. The Twitter comments could be taken as an intention to reevaluate and a hope to be able to remove, the order within 100 days. In any case Twitter comments are not legally binding, nor are press conference statements or other public statements by the President.

Evert if the order had contained a fixed sunset date, the President could always issue a new order extending this one at any time.

Note also that the order only instructs department heads to "take action, as appropriate and consistent with applicable law." This leaves significant room for judgement as to what is "appropriate."