Insurance credentialing and contracting fluctuates based on the area of the country and the provider’s unique situation. On average, it takes 90-120 days to become in-network with your major carriers. Credentialing takes about 60 days and contracting takes another 30-60 days depending on the carrier.Medicare enrollment can take up to 180 days but our average is around 55 days depending on what we are doing. Reassignment applications for an enrolled provider take about 40 days.edicare enrollment can take up to 180 days but our average is around 55 days depending on what we are doing. Reassignment applications for an enrolled provider take about 40 days.