Retirement benefits can be based on various factors, one of which is indeed an individual's income prior to retirement. Retirement plans such as pensions often take into account the length of service and average salary earned by the employee over their career in order to calculate a benefit amount upon retirement. The formula used may involve variables like years worked and earnings history in order to determine the retirement benefit amount an individual will receive monthly or annually after retiring from employment. Apart from income-based calculations, factors like age at retirement and specific eligibility requirements can also impact the overall retirement benefits received by an individual.