I always figure visually I can be spotted at 5 miles daytime, 3½ miles night, 5 miles by aircraft.
I consider I should be at silent running with an escort within a mile. I don't care what range active can pick me up because I plan on losing them even when I'm well inside that distance, whatever it is. When they hit the active I get busy and hit the jets to get out of there. That's usually when I'm able to break contact and slink away.
I have found sometimes that periscope depth is a good depth when they're actively pinging. Don't know why, but they seem to have more trouble locating me sometimes, but beware, there is less room for error there. I find myself getting more aggressive with escorts lately since I hate them so. Oh, I forgive them, but I hate them.
