An Object Repository is a centralized location (like a .properties, .json, or Excel file) where all locators are stored. Instead of hardcoding locators in test methods, you reference them from this central repository. If a button's ID changes, you only update it in one file instead of 50 different scripts. This follows the DRY (Don't Repeat Yourself) principle and makes maintenance much easier.
Without Object Repository: 50 scripts have `driver.findElement(By.id('loginBtn'))`. The ID changes, and you must update all 50 scripts. With Object Repository: All scripts reference `OR.getLoginButton()`, and you only change the property file.
How does an Object Repository help in a project with 5 team members?