Paint or reupholster an old sofa, which option is better?

Upholstering is almost always the better option because paint will peel, crack, and get stained by anything, while new fabric or leather gives you years of use. If the couch is in good structural condition but the fabric is just worn out, reupholstering it leaves it looking brand new; painting is cheaper but it's a temporary fix that ends up looking bad after a short time. Also keep in mind that upholstery protects the padding better from deterioration and dust, so it's really worth the expense.