You might keep your money in a bank, but have you heard of a time bank? This online service allows users to trade

services with one

another without exchanging money. For example, a hairdresser gives

someone a haircut for one hour of credit in the time bank. The

hairdresser could then use that credit to have a plumber come work for

her for an hour. Time banks are useful for people who can't arrange

direct trades. The plumber might not want a haircut, but he can work

for the hairdresser and earn credit to use with someone else.

How does the detail "The plumber might not want a haircut, but he can work

for the hairdresser and earn credit to use with someone else" best support

the central idea that time banks are a convenient way to get things done?