  We study the revenue-maximizing mechanism when a buyer's value evolves
endogenously because of learning-by-consuming. A seller sells one unit of a
divisible good, while the buyer relies on his private, rough valuation to
choose his first-stage consumption level. Consuming more leads to a more
precise valuation estimate, after which the buyer determines the second-stage
consumption level. The optimum is a menu of try-and-decide contracts,
consisting of a first-stage price-quantity pair and a second-stage per-unit
price for the remaining quantity. In equilibrium, a higher first-stage
valuation buyer pays more for higher first-stage consumption and enjoys a lower
second-stage per-unit price. Methodologically, we deal with the difficulty that
due to the failure of single-crossing condition, monotonicity in allocation
plus the envelope condition is insufficient for incentive compatibility. Our
results help to understand contracts about sequential consumption with the
learning feature; e.g., leasing contracts for experience goods and trial
sessions for certain courses.
