Identifying the leather before anything touches it
Almost every leather mistake comes from treating the wrong type. Pigmented or protected leather carries a surface coating and is the most common in family furniture; it tolerates cleaning well and shows wear as coating loss rather than staining. Aniline leather is dyed through with no protective topcoat, feels warm and natural, and absorbs everything including water spots and body oil. Semi-aniline sits between the two. Nubuck and suede have a raised nap and must never be wet cleaned in place. A simple water-drop test on a hidden area tells us most of what we need: if the drop sits on the surface the leather is protected, if it darkens and absorbs it is aniline and the entire approach changes.