Michael Linton originated the term "local exchange trading system" (LETS) in 1983 and for a time ran the Comox Valley LETSystems in Courtenay, British Columbia. LETS networks use interest-free local credit so direct swaps do not need to be made. For instance, a member may earn credit by doing childcare for one person and spend it later on carpentry with another person in the same network. In LETS, unlike other local currencies, no scrip is issued, but rather transactions are recorded in a central location open to all members. As credit is issued by the network members, for the benefit of the members themselves, LETS are considered mutual credit systems.
For instance, let's say your pipes burst at your home and you find yourself in need of a plumber. It's an emergency situation and if you don't hire a plumber fast, you'll be displaced and will have to move your family out of the house and into a temporary living situation. That certainly would be a bad thing. But should you barter your dog grooming services right now? Do you really want to trust your plumbing to the only person in town who'll do the job if you shampoo their poodle?