Confusing Contract with Trade is a very common error. Trade is whole and complete at the moment of trade. That which is received is valued more than that which is given away in exchange. Contract is a conditional PROMISE to trade or keep trading at a future time along terms established in the present tense of a trade. As such, a contract is a GOOD, an element of trade, and not trade itself.
Contracts, promises, have subjective value just like any other good. The market has evolved to measure and value the risks of promises, such as credit ratings, default deposits, insurance, etc.
Contracts cannot be enforced beyond the return of any and all goods or services (or their market value) which have been exchanged PRIOR, without violating the voluntary volition of acting individuals. People can freely change their mind whenever they want for whatever reason they want. You can quit your job whenever you want for whatever reason you want. You can promise somebody something and then change your mind without causing any harm to anyone. This is why contracts have “risks”. If the terms of a contract could theoretically be enforced, such a concept as risk would never have evolved, and the terms of all contracts would adequately apply the exact same to all individuals regardless of their varying means or abilities. Yet we do not observe bakers being awarded contracts to build skyscrapers; though if the terms of a contract could be enforced, there would be no difference for someone purchasing a contract to build a skyscraper from a baker than there would be from purchasing a contract to build a skyscraper from a construction company. Bankers take risks when they trade money for the promise of money plus interest in the future.
We also observe contracted wages generally being paid in relatively shorter terms such as bi-weekly or monthly, rather than yearly or by the decade. That’s because subjective valuation is not constant, and it is impossible to know the exact subjective value of terms in the future. Employees can be fired. Employees can receive wage increases. New trade contract terms can compete with old trade contract terms, thus assuring all individuals have constant access to the absolute best deal trade terms which can be had, due to free trade competition.
Contracts can be cancelled at any time, and are cancelled when continuing to perform the terms of the contract is less valuable than not continuing to peform the terms of the contract. People who generally fulfill their contracts are subjectively valued higher than people who generally don’t fulfill their contracts. And continuing to fullfill terms that may be minimally unfavorable can occur if the actor values more the reputation gain from fulfilling the contract. The market analyzes and evaluates the trustworthiness of individuals, precisely because contracts are not enforceable. But credit and reputation have subjective value just like gold has subjective value. And that is why contracts are SELECTIVELY traded.
Thus, it is an oft repeated error that someone can contract themself into perpectual slavery. They cannot, precisely because contracts can be cancelled at any time. This is why we also observe such actions as “contracts being renewed”, or renegotiated, along lines that insure both actors are constantly increasing their subjective wealth from present tense trade.