We’ve all faced a situation where we had to wait days for a doctor’s appointment. Once you finally get there, you feel rushed to recount how you’re feeling before you’re ushered out the door.

So it’s not surprising then that direct primary care (DPC) — commonly called concierge medicine, which was introduced about 20 years ago — is a rapidly growing field.

Concierge medicine is a system in which you pay an additional fee for increased access to your doctor. To access this type of care, you need to pay a charge on top of your usual health insurance or Medicare plan. The average fee is between $1,500 and $2,400 ($125 to $200 a month), according to Concierge Choice Physicians.

The chief advantage of concierge medicine is greater access to your doctor. That’s because a concierge physician will have between 150 and 600 patients, while a traditional practice might serve up to 5,000 patients. This allows for longer appointments, more frequent follow-up care, and increased emphasis on prevention and wellness. Patients are also often given day-and-night access to their physician by phone.

Doctors like the practice because they can spend more time with each patient, and have a stable source of income. But many patients appreciate it as well.

The biggest limitation of DPC is that it’s not insurance or a replacement for it. It really only works as an add-on to your existing health plan. And because DPC covers only a narrow range of services, you still need to pay premiums to maintain regular health insurance for specialized treatments or catastrophic care.

And if you need a higher level of care than your DPC doctor can provide, you’ll face deductible and out-of-pocket costs as well.

Concierge medicine has become a national trend, but most practices tend to be located in places with high numbers of seniors who see their doctors regularly, such as California and Florida. This makes sense, because patients with chronic conditions are more likely to need such enhanced access to medical care.