When it comes to family I could go an eternity without talking to them. Probably even for immediate family. Which it isn't that I don't like my immediate family it's just I never feel an urge to go out of my way to talk to them. So I could see myself going a very long time without speaking to them if I was ever far away.
As for friends I've gone whole summers without talking to any of them and then when I go back that first day of school it's like we've been talking the whole time. After not speaking to a friend for a year or so I would consider the friendship over in the sense of closeness. Once I start talking to them again though it's usually like nothing has changed. I've had quite a few friendships that were strong, then died off, and then came back together just due to being apart and coming together again, so I know it's easy to do!