Minimum amount of time before unfriending

I guess I'm pretty harsh. I give about a week, on average. The way it typically works out is that I don't notice they're gone until there's nothing to tap. On a typical max-level town, that might take anywhere from 4 days to a week. I start paying attention when I have to check their Krustyland for something to tap. By the time everything's gone, I take a look at how long they've been offline. If it's less than 3-4 days, I give them a little more. If it's close to or more than a week, I drop them. There are exceptions: if I see a message saying they're on vacation, or if I particularly like their town or know them from the forum, I give them more leeway.

But basically, I usually have at least 10 friend requests pending because people keep randomly sending them. I don't really sweat losing one random for another.