You may have a regular doctor, which is a good idea, but most doctors’ offices are open only during regular business hours, which means roughly 8 a.m.-5 p.m. Monday-Friday. What happens if you get sick or injure yourself outside of those hours? You could go to the emergency room, but that can be very expensive, and if it’s busy, you could have to wait for hours. A better alternative for your after hours ills may be an urgent care center.

Urgent care centers offer the kinds of services you would get at your doctor’s office, such as treating colds, the flu, strep throat, other illnesses and minor injuries such as sprains. They might be standalone clinics, or they might be inside other retail businesses, such as a pharmacy, grocery store or discount center. An urgent care clinic visit typically costs a little more than a regular doctor’s visit, but it is much less than visiting an emergency room.

Walk in clinics typically are open well into the evening, often as late as 8 or 9 p.m. And about 85% of them are open seven days a week. The most common reason that people go to such centers is for some type of respiratory infection. About 3 million people go to a walk in clinic each week, and although many go because of an illness or injury, others use such facilities for preventative care. Most urgent care centers offer flu shots and other types of vaccinations. Many also offer sports and school physicals for children. For people without insurance and a regular doctor, such facilities can play a critical role.

There are some things that urgent care centers cannot take care of. While many centers offer x-rays, if you have a broken bone, you likely will have to go to the emergency room. Serious trauma from a car accident or other event also should be cause for an ER visit and not a walk in clinic.

Another thing to keep in mind is that you may not see a doctor when you visit a walk in clinic. While there are around 200,000 doctors working in urgent clinics, many are staffed by physician assistants and nurse practitioners. If you feel you need to see an actual doctor, it may be better to make an appointment at a medical practice.

When you get sick or injured after hours, urgent care makes a lot of sense. You will be able to get care quicker than at an ER, and it will be much less expensive.