Edge-to-center search checklist, retrace method, likely visual misses, common mistakes, stuck fixes and no-guarantee boundary.
Stop roaming randomly. Return to the last unfinished section, trace its outside edge, then sweep inward in narrow overlapping lanes.
A missed leaf is easier to spot when you reduce the search area. Check behind visible piles and structures, change the camera angle, and recheck the line where cleaned ground meets uncleared ground.