Team member laptops can be refreshed after 3 years of use without question. However, if the replacement laptop is outside the standardized specifications listed here, then manager approval will be required before IT can purchase the replacement laptop. If you feel you need a new laptop to be effective at your job before then, reach out to IT and your manager.
Team member laptops can also be replaced before the 3 year period if the replacement is justified (ex. damanged laptop). If your laptop is broken and needs to be repaired, you can take it into an Apple Store or reseller for repairs. You should ensure that you have a recent backup before doing so, and that your laptop is not your only registered device for iCloud two-factor authentication.