Model:
Model properly sized in mm unitsModel has no hidden/frozen elements, no groups/linked objectsNo lights, cameras, helpers, layers, particle viewAll elements has 100/100/100 scale and correct normalsNo any modifiers in stack except of turbosmoothElements properly namedMaterials and maps:
No missing texturesNo unnecessary maps in environment / background / unwrap modifierMaterial editor resetted, all paths stripedMaterials and textures properly namedGeneral:
No 3rd-party plugin usedNo ALC and CRP viruses