Wage dispaities occur when two employees who work for the same firm perform identical tasks but earn different salaries.
Do you reward your employees with wages according to length of service?
Those who have been with you the longest are the ones you have invested the most in, in terms of training, inside information, etc. They are, therefore, the most adept at sorting out the day-to-day issues that arise at your company and, thereby, are the most worthy of more pay.
The most senior employees serve as mentors to train junior staff and should be compensated accordingly.
A higher salary for those with more seniority is an incentive to maintain or increase their loyalty to the enterprise as well as boost the retention and satisfaction of senior staff members.