What Is It About 15 Minutes?

I was talking with a friend yesterday when the subject came up of how people measure time.  I'm not talking about how long a second or minute is.  What I mean is how perception correlates with certain incremental time values.  We came to the conclusion that 15 minutes is a major time value.  What is it about 15 Minutes?

• Waiting in the doctor's exam room. - A 5 or 10 minute wait is fine but once 15 minutes is reached, your temperature boils and you feel devalued and mistreated as a patient.

• Showing up for a doctor's appointment. -  Less than 15 minutes late and nobody cares.  Once you've surpassed the 15 minute mark, you must reschedule your appointment.

• Business Meeting. - Show up 10 minutes late and your counterpart will likely say something like "I just arrived too".  Let the minute hand strike 15 and you'll receive a phone call wondering where you're at.  

• Meeting a Client - Show up 5 minutes early and the person you're meeting with will begin to prepare for your appointment.  Show up 15 min early and your client will feel rushed and as if you're pressuring.  They'll also likely stall you until after your scheduled meeting time.
  

Just an observation here.  I also believe this time buffer is shrinking due to the instant real time world that the net has given us.  

My general rule of thumb is to never be late to a meeting and to never arrive more than five minutes early.  This generally means arriving in plenty of time to allow for any unexpected slow downs.  But then sitting in the parking lot until the 5 minutes prior mark is reached.

Your thoughts on the subject?

JC