A long-term disability plan provides a source of income if you cannot work because of illness or injury. This helps you maintain a percentage of what you earned before you became disabled. Adjustments are made over time to help protect against inflation. Example: A disability plan pays 60% of your salary. You earned $50K before you become disabled at age 40. With no adjustment to your income, inflation would greatly reduce your buying power by the time you reached age 60.