Full-grain leather uses the top layer of the hide with its natural markings and texture intact; it's the most durable and expensive grade, develops a patina with use, and is the only grade that actually improves in character over years of wear. Top-grain leather has the surface sanded and often embossed with a uniform grain pattern, correcting for natural imperfections; it's more consistent-looking and still genuinely durable, just less individual. Bonded leather is leather fiber scraps bonded to a fabric backing with polyurethane — it looks like leather when new, but the surface layer typically peels or cracks within two to five years of regular use, and it should be priced accordingly.
Aniline leather is dyed but not surface-coated, so it shows the hide's natural texture and marks and feels the softest — but it's also the most prone to staining and fading and needs conditioning. Semi-aniline and pigmented leathers add a thin protective topcoat, trading a little of that natural feel for real stain and fade resistance, which is why most leather sold for family use is one of these two, not pure aniline.
Leather should be kept out of direct sun and away from heat vents, both of which dry and crack it faster than normal use would. A leather conditioner applied every six to twelve months keeps the surface from drying out; a store that sells leather furniture without mentioning this is skipping a detail that materially affects how the piece looks in five years.
Leather also runs warmer and cooler with the room, unlike fabric — worth a mention if the piece will sit in a sunroom or near a fireplace, where temperature swings are more extreme than in a typical living room.