The strongest routine includes a version for difficult days.

Any routine that only has one setting is fragile, because life comes with settings of its own. Building a deliberate low-capacity version means the hard day has a plan attached to it rather than a decision to make while depleted. Decisions made while depleted almost always come out as nothing.

Write the reduced version down before you need it. Give it a name so it feels like a legitimate option rather than a failure. Then a hard day becomes a different mode instead of an exit.