Loss, Deterioration, or Improvement:
a. Without fault of the seller – obligation is extinguished
b. With fault of the seller – liable for damages
a. Without fault of the seller – the impairment is borne by the buyer
b. With fault of the seller – the debtor has two options: to exact fulfillment and ask for damages, or rescission with damages
a. By nature or time – the improvement benefits the buyer
b. At the expense of the seller – the seller has no other right than that granted to the usufructuary