The optimal solution in terms of medical care would be applying for a commercial student insurance policy. However as this can get extremely expensive, we either have to accept the fact that our children may suffer from inadequate health care or we have to start juggling the various policies to give them the best for the lowest cost.
There are four common problems you have to cope with while choosing the student policies: access to medical facilities, catastrophic medical expenses, international coverage and sport injuries.
Access While commercial student health insurance policies offer access to all medical facilities, it is usually enough if our children have the medical care at the campus and at home. In terms of accessibility, combined parents' and college health plan coverage is the most cost-effective solution, though they can't cope with large medical expenses nor outside-the-U.S. treatments.
Catastrophic medical expenses If you're worried about some major health problems, accidents and the like, the only policies that can really help you are commercial ones. However, you can lower the premium considerably if you choose a high deductible. The most popular choice is a $2500 deductible. This keeps the monthly premium on a reasonable level of $60 or so.
International coverage Don't look for a policy that would cover medical expenses abroad, it would be very expensive. Buy a separate travel policy instead. As it will cover only the time your children really spend abroad, it will be relatively cheap.
Sport injuries One of the main sources of injuries suffered by college students are sport injuries. While all college health plans insure sport injuries, this is not the case for many parents' health plans. If you decide to resign from the college health plan, make sure that the sport injuries are explicitly covered by your other policies.
Short-term policies - best solution? Another option to keep the high level of medical care at a low price is to go for a short-term commercial policy instead of typical student health insurance plans. For example, you can buy the policy only for the exact time your children spend at the college and let your parents' health plan cover the rest. What's more, many short-term policies offer better-than-usual coverage for a price than is roughly 2/3 of what you pay for a similar commercial student health insurance.
Probably in most cases a short-term policy supported by the parents' health plan and separate travel policies when needed will be the most cost-effective solution, giving your children almost all benefits of typical commercial student insurance policies for much lower cost. However, if it is still too much, the standard parents' health plan plus the college student health plan will (in most cases) be enough.