If you’re packing a child off to college this summer, the extra-long sheets and shower caddies can wait. Health insurance should be at the top of your to-do list.

Many private colleges and public universities require full-time residential students to have health insurance, and some aggressively market their own plans, automatically enrolling incoming students in their insurance plan and adding the premium — which can be several thousand dollars a year — to the tuition bill. If you don’t need it and want to get the charge removed, you must meet the college’s early and often rather arbitrary deadline for proving your child is adequately insured and obtaining a waiver. (This is not a one-and-done, by the way. You must obtain the waiver every year.) Policies vary by school. Some, like the University of Michigan, make health insurance mandatory for foreign students but not for domestic students.

If you’re lucky enough to have an employer-provided family health plan, most experts recommend keeping your child on it. Dependents can be covered on a family plan until age 26 under the Affordable Care Act, or Obamacare; it’s one of the few components of the A.C.A. that has strong bipartisan support. But no matter how your kids are insured, you’ll need to do some fact-finding to make sure they can get access to health care services in their college town and figure out how much it might end up costing you.

When we packed our oldest daughter off to college, we obtained the waiver but worried. Our family’s employer-provided health plan was excellent, but the university — which was promoting its student health insurance plan — warned us that the health center on campus did not participate in any insurance networks other than the university’s own plan. As a health writer, I knew that meant we could be stuck with some pretty steep bills.

We briefly considered switching to a different plan with a larger network of doctors in the college town — and finally started making phone calls and asking questions. What we found out was that it didn’t really matter what insurance our child had: Full-time students could go to the university health center for primary care services for a $10 co-payment, just by virtue of being students. (The service was covered by a mandatory student activity fee.)

Every university can craft its own policies, but many colleges and universities have clinics that provide primary care services to students, often at nominal prices or even free, according to College Parents of America, a group that promotes completing college, and American College Health Association, a nonprofit association of college health professionals. The clinics often provide student basics like contraception and mental health counseling. But you still need comprehensive insurance for big-ticket items like hospital stays, surgery or more serious illnesses.

“Generally speaking, I would never remove a child from a family plan,” said Stephanie Cohen, a partner in Golden & Cohen, a health benefits consulting company based in Gaithersburg, Md. Most other plans, she said, “are not going to have the kind of coverage you have under your employer-provided group plan.”

Still, you must talk to your human resources department, insurer or broker about how students can access care when they’re away from home, in a college town or abroad. That’s especially important if your insurance is a closed network like a health maintenance organization, with no coverage for out-of-network care. But even if you have out-of-network coverage, it’s more expensive to obtain care from doctors and other providers who do not participate in the network.

The one exception is emergency room care: Under the A.C.A., insurers cannot charge you more for seeking care at a non-network emergency room, as long as what you are experiencing is a true medical emergency.

“It’s absolutely critical to talk to your insurance provider about what networks are available in terms of getting care out of state or out of the country,” said Shelly Waggoner, vice president of human resources at Medical Group Management Association, an association that serves the medical group practice industry. Some plans may offer a so-called away-from-home option that allows for more flexibility in accessing care for the college student at a residential campus in another region, but you’ll need to check, she said.

If you think you can save money by removing a child from a family plan and placing him or her on a student plan, make sure you consider all of the out-of pocket costs the change would entail, including copays, coinsurance, deductibles, and drug and lab coverage – not just the cost of the premium.

A lower premium doesn’t mean the coverage will cost less because plan designs and out-of-pocket costs vary so much, Ms. Waggoner said. “It’s not an apples-to-apples comparison.”

While employer plans are usually fairly generous, other plans may require the patient to meet a high deductible before medical care is covered, for example. “It’s critical for families to analyze the plan design over all and think about what kind of care their child requires on an ongoing basis,” Ms. Waggoner said. “Are they somebody who needs to regularly see their physician? Are they covered by the plan, and at what level, and how much is out of pocket? You have to think about the true cost of care.”

Under certain circumstances, like when a child has a chronic health condition that requires intensive ongoing management that can’t be covered adequately under the family plan, you may want to purchase a separate plan, said Stephen Beckley, of Hodgkins Beckley Consulting, which does consulting for colleges and universities about college student health programs. “It’s a risk assessment,” he said. “Everyone must look at their own situation.”

Though people of college age tend to be fairly healthy, new health needs often emerge during these years, whether it’s a need for birth control or treatment for anxiety or depression. They’re also at high risk for accidents and injuries.

Young adults may not realize that despite medical privacy laws, many insurers routinely send a form called an explanation of benefits to the policyholders — which would be their parents if they’re on a family plan — after each bill is processed. It may contain specific information about the service provided or name the facility and provider, though patients may request that insurers not disclose confidential information.

If the student needs to buy his or her own health insurance plan, there are several options, including the college or university’s student health plan, an A.C.A. plan that you purchase on the exchanges, or, for students with financial needs, Medicaid. Ask whether the plan you’re considering will cover the student year-round, even off campus.

Student health plans today provide comprehensive coverage because they must conform with most of the requirements of the A.C.A. (at least for as long as the act remains in place — that could change). Make sure you understand the plan design and the associated costs.

Students who purchase an A.C.A. plan may be eligible for subsidies. But parents need to be aware that if a student is claimed as a dependent on the parents’ taxes, then the parents’ household income will determine the student’s eligibility for premium subsidies, according to John Fees, a member of the board of directors of College Parents of America. Again, make sure you understand the full costs of care, beyond the premium.

“It’s important to be proactive about understanding the options that are available to you,” Ms. Waggoner said. “When you think of all the things you need to do in preparing for children going to college — dealing with student loans, housing, registering for courses — this often ends up on the back burner.”