I agree with Mr. Ambash's suggestions concerning a careful review of personnel policies ("Employers Face Stiffer Tests in Firings," Insider, October 1985). The crucial concern for the small-business person should be to create the perception of fairness in termination decisions. Some employees, like it or not, deserve to be fired. If they remain in your employ, other employees will take advantage of what they believe to be leniency or indecision. The classic statement of employment-at-will is the power of either the employer or the employee to end the relationship "for good reason, bad reason, or no reason at all." The smart employer, however, fires for good reason -- why else discharge someone who represents a substantial investment in time and money?