Use when shading an asset in Maya with Arnold: OpenPBR or aiStandardSurface materials, hooking up Substance Painter or UDIM texture sets, color spaces (sRGB, Raw, ACEScg), a normal map that looks wrong, displacement with black holes or faceting, skin SSS, chrome and metals, glass or crystal, car paint, aiStandardHair, porting Standard Surface to OpenPBR, or a lookdev turntable with chrome and gray balls. Also when textures render washed out, too dark or plastic in Arnold.