Coinsurance is your share or percentage of covered expenses you must pay in addition to the deductible. The most common coinsurance arrangement is for the insurance company to pay 80% and you pay 20% as coinsurance until a maximum out-of-pocket expense is reached. Coinsurance applies to each person and starts over again each year. Sometimes the policy will cover all expenses after a certain point. Look at the list of covered expenses for the policy to see how comprehensive it is.