Why does having health insurance before being diagnosed with a serious condition make a difference?

Health insurance, pre existing condition?

• what is the difference between a pre existing condition in health insurance and pre existing condition exclusion period. im reading from howstuffworks, health insurance but still confuse. i understand employer waiting period. here is the link for pre existing condition http://health.howstuffworks.com/health-insurance12.htm here is the link for pre existing condition exclusion period http://health.howstuffworks.com/health-insurance13.htm

• Answer:

  A pre-existing condition is something that you had or were being treated for prior to getting your insurance. Some group insurances will have a waiting period once a new employee signs up for the insurance if they have a pre-existing condition. This waiting period (where the insurance does not cover the condtion) is called a pre-existing exclusion period. Once the employee has had the insurance for the length of the exclusionary period (usually 12 months), then the condition is no longer excluded, but is considered a covered condition