It depends on what time of the year. When hunting during the daytime with the exception of first light and last light, I am typically pulling them from cover. I have an exact area in mind. In these situations, I only stay about 15 minutes because I am targeting a small area for coyotes.
When nighttime hunting very open areas, I stay a lot longer with the average between 22-30 minutes. They can be coming from any direction and often are coming from longer distances. Yes, you can get more stands in by doing shorter stands. However once you factor in the time it takes to walk to a stand, put the call out, walk back from your stand, and drive to the next spot sometimes it pays to stay longer on stands you have a lot of confidence in.
Always continue calling and also change up your calling strategy. I am not saying try 15 different sounds on the same stand, but try to trigger a different response. If they don't seem hungry, playing 10 different rabbit distress sounds probably isn't going to help. Try to get a territorial response, social response, etc.
The stand that I posted in the Night Hunting Section on Predator Masters last year where I shot
7 On The Same Stand , I used 3 calling strategies on the same stand. I started off with very soft distress, once I had shot the first few and things slowed down, I moved to louder more aggressive style distress which brought in a couple more. I then switched to vocalizations and finished the stand with 7 in total. Yes, this stand took 45 minutes from beginning to end. I could have maybe got one more stand in during this time considering drive time, set up time, walking to and from the stand.
A suppressor helps but I have still called lots of multiples after shooting multiple coyotes without one.