Restrictions to prevent competition by a former employee are held valid when they are reasonable and necessary to protect the interests of the employer. For example, a provision in an employment contract which prohibited an employee for two years from calling on any customer of the employer called on by the employee during the last six months of employment would generally be valid. Courts will closely examine covenants not to compete signed by individuals in order to make sure that they are not unreasonable as to time or geographical area.
If this covenant not to compete is entered into at the time the employee is employed, the promise of the employer to employ and pay compensation is consideration for the employee's covenant not to compete. If the employee's promise is made after the original hiring date, and the employee does not have a contract of definite duration in time (employment at will), then the covenant would be binding on the employee in many states because the employer would be able to fire the employee if the employee did not enter into the contract. Some Courts do not follow this reasoning and will not enforce a covenant not to compete by an employee already employed (whether by written or oral contract). If the employee has a five-year contract, the employer cannot enforce a new provision, such as a covenant not to compete, unless new consideration is given, such as money. The employer is not giving any consideration in such a situation.