At what point do you move on?

This has been on my mind a lot lately. Mike and I moved to Texas a little over a year ago. Before that we were in Orlando for 3 years (Mike was only there 1 1/2), and before that our respective college towns for 3 and 4 years. And then before that our "home towns." Naturally we have friends from all of the mentioned locations. I think I am better at keeping in touch than Mike (with the exception of his college guys), and perhaps better than most people on the planet, but at what point does a person stop trying to keep in touch? Does it vary for every relationship?

Should I call my friends from high school trying to hold on to those times from 7-10 years ago? Even when the conversation may feel forced? If I don't - what will the 10 year reunion be like? "I have no idea what is going on in anyone's life that they didn't write about on their myspace or facebook."

Should I try to maintain those friendships from college? Obviously, some relationships will maintain themselves. But what are the odds of me ever seeing most of those people again. Unless we start having reunion tailgates (which is pretty far off for me, seeing as how we live in Texas).

What about Orlando? Most of our friends from there have now moved also. We have no neutral ground anymore? Will I ever see them again? I care about these people, but at what point do I stop investing in those relationships and start investing more in people here in Texas.

Of course there are friends that don't fall into this category. Alyse Smith has been my friend since I was 5 years old. 21 years! And when I talk to her it's like we are sitting in the same room. Our conversation seem few, but it doesn't matter how long it's been, I always enjoy chatting.

So how do I know which to give up on...and which to work on?