The assumed-fixed

Dates treated as immovable that are actually habits — and are usually the cheapest flexibility available.

The deliverable

What it is

Alongside the genuinely fixed dates sit a larger number that are fixed only because they have always been there.

Testing them is what creates the flexibility to resolve collisions, and the test costs nothing but asking.

One level in

Each element is a constituent part of the component. Follow one to see the attributes it carries.

The candidates
Which dates have no external authority behind them.
3 attributes: Date · Why it is when it is · External authority
Learn
The dependencies
What has grown up around the date.
3 attributes: Depends on it · Expects it · Cost to move
Learn
The test
What happens if it moves.
3 attributes: Moved to · What happened · Kept
Learn

Ask of each fixed date who fixed it. Where the answer is that it has always been then, it can move.

The dates that genuinely cannot move — a short list, and shorter than the one most organisations carry.

When change is not allowed, because the cost of getting it wrong is at its highest.