Each year, the government sets aside a specific time called Open Enrollment period (typically November 1st to mid-December) where anyone can purchase a new insurance plan for the coming year.
The government created this time because insurance works by combining the money that people pay each month in premiums to cover medical costs. Without Open Enrollment Period, many people would only apply for insurance once they got sick or required expensive medical care, and there would not be enough funds in the system to cover everyone’s medial costs.
Outside of Open Enrollment, people may qualify for a Special Enrollment Period. During this time, the government requires that individuals have a qualifying event (click here for the full list of qualifying life events!) that has occurred within the last 60 days to apply for a new health insurance plan or switch plans. Also keep in mind that in most cases, this event should have led to a loss in prior health insurance coverage.