(adjustable) delay
One of the features on my custom PRO-10 & PRO-77 scanners is adjustable delay. I typically use a delay of 2.9 seconds for all standard conventional channels. I added it because the "2 second delay" in Radio Shack scanners is barely 1 second in reality and I want to hear an entire conversation before scanning off to the next.
Using scanners like the PRO-97 or PRO-164 is very frustrating. I don't know how anyone can listen to stuff with Delay set to off. And with it on, 1 second is not enough before it scans off. With 1000 frequencies (not including the myriad of talkgroups), you're unlikely to ever hear a complete conversation.