Solving this problem has always been a slippery slope. Charging patients a fee for not showing up or failing to cancel 24 hours prior to the appointment can seem antagonistic and turn patients off to your practice. Yet letting a few patients continue their lax or tardy behavior at the sake of not providing care for those that are in need can be costly as well.
There are ways to solve this problem that satisfy both patient and doctor. What got me on this topic in fact was an article that described one really innovative solution:
"We added a new doctor - first name "Virtual," last name "Physician" - into our scheduling database. When our habitual no-shows scheduled an appointment, we place them on Dr. Virtual Physician's (or Dr. VP, as we have come to call it) wide-open calendar. The primary care physician's schedule is not affected by the chronic no-show's appointment. If the no-show patient does appear for the appointment, they are placed in the queue behind the on-time patient."EDIT: Doctor's offices do get walk-ins (GPs, Pediatrics, etc.), but the timings are never predictable. Regardless, keep in mind that doctor's offices keep very static schedules. A lot of practices use the virtual scheduling solution above to block off times daily or on Fridays for catching up on administrative activities. The reason they don't just fit it in when a patient doesn't show up is because the expectation is that there is a real medical reason for the visit and many potential medical reasons for a delay. So time lost due to a no show is all real time.