I think time per stand is dependent on available acres to hunt, hunting pressure, weather conditions, competition or hunting for fun. Ex. If I have 500 acres, I’ll spend significantly more time per stand than I will on 20,000 acres. But if you’re hunting large ranches then yea 15 min per stand is fine. Some guys hunting large west Texas ranches in competitions make 5 minute stands. On my family’s 1500 acres, I do about 45 mins, and after 30 minutes I’m typically sitting with the expectation of seeing bobcats since I haven’t seen coyotes yet.