The checklist is the cheapest safety equipment on the aircraft, and the first thing a quick-turn mission tempts you to abbreviate.
Every HAA pilot knows the pattern. The tones drop, the clock starts, and a flow you have run a thousand times begins to feel like the checklist itself. It isn't. The flow sets the aircraft up; the check verifies it. When the two collapse into one, the verification step is the part that disappears.
Where the discipline erodes
Erosion rarely announces itself. It shows up as a challenge read while the hand is already past the switch, a response given from memory instead of from the panel, a "checklist complete" that arrived a beat too early. None of it changes the outcome — until the day the aircraft wasn't configured the way the flow assumed.
Keeping it intact
The fix is not more checklist; it is a harder boundary around the one you have. Fly the flow at mission speed, then run the check at checklist speed. The seconds involved are trivial against the block time of any leg, and they are the only seconds in the sequence whose entire job is catching the error you already made.
(Filler text for layout and workflow purposes.)