At similar casting speed the pause gets longer as the line gets longer: with comparable line speed and loop conditions, 45 ft of line takes longer to straighten than 20 ft, so the next casting stroke starts later.

Time the next stroke to the line straightening, not to a fixed memorised pause. Start each stroke when the line and leader are almost but not quite straight; the count that worked at 20 ft will be too short at 45 ft.

The Fifth Essential ties the duration of the pause to the amount of line outside the rod tip. Two things set it in practice: line length and line speed. Hold speed constant and only length is left. Too short a pause and the line has not unrolled, giving slack and a whipcrack or an undulating line; too long and the line falls and ticks.

Distance also changes trajectory. At 20 ft the pitch is steep, up in back and down in front; at 45 ft it is shallower, with loops kept to 4 ft or less.

Source

From the Fifth Essential and the trajectory section of the CI Study Guide (2025) (PDF), and Task 21’s rule that the pause needs to be longer as the cast lengthens; terms from the FFI Fly Casting Definitions (Pause, Trajectory). See also Task 12, accuracy on-side.