The sight check
Lift one end to your eye and sight down the edge like a rifle barrel: crowns (banana bends), twists, and crooks announce themselves instantly. Set crowned boards aside for short spans or crown them up in framing (joists crown up; the floor flattens). Eight seconds per board sorts a pallet into good, usable, and leave-it.
The checks beyond straight
Check ends for checks (splits) and shakes, faces for knots near edges (they weaken and bleed), and edges for wane (missing bark edge). For visible work, grain orientation matters too — flat-sawn boards cup toward the bark; cabinet carcases alternate orientation. All of it is faster to see than to describe; the yard expects you to look.
The return policy is your friend
Yards accept uncut returns — which means buying 10% over and returning surplus costs the fuel only. The pros over-buy deliberately. Combined with the sight-check at the rack, you bring home the good boards AND the right count; the pallet's banana collection stays at the yard.