You can expect a health insurance policy purchased on the healthcare.gov exchange to cost as much as $10,000 - $12,000 per year. This can be reduced if you have income low enough to qualify for special tax credits.
For early retirees with significant IRA and 401(k) savings, this presents a problem because withdrawals from these pre-tax retirement accounts will count towards taxable income and may disqualify you from these valuable credits.
A financial plan that is created a few years before early retirement can be incredibly valuable to ensure you can find affordable health insurance options in retirement before you are eligible for Medicare.