Most companies will make it effective next day as long as you don’t have any ongoing/unresolved health problems. However if your medical situation is more complicated they can push the effective date back till they have answers. The insurance company will most likely ask to view medical records and/or receive an attending physician statement which because of the snail pace in medical records departments can take up to 18 business days - in other words about a month. Best advice? Start looking for insurance about 30 days before your current coverage will cease to give the underwriting department for your new company time to handle any snafus.