Question

at what point does buying in bulk stop being a wise spending choice?
when bulk items are not on sale anymore
when costs rise too quickly due to demand
when the consumer has a lot of space to store bulk items
when the consumer buys more than is needed

Explanation:

Buying in bulk is wise to save costs, but if a consumer buys more than needed, the excess may go to waste (e.g., perishable goods, unused items), negating savings. Other options: having storage space supports bulk buying; cost rise due to demand is about market, not bulk's wisdom; sale end just means no discount, but bulk's wisdom is about need vs quantity. So buying more than needed makes bulk unwise.

Answer:

when the consumer buys more than is needed