1. All my connects are usually based on personal matters--- interests, hobbies, personal relating, etc so it's easy to make plans to do things you already do anyway.
2. I'm an introvert and like I said, a bit of a recluse, so I usually dump people on my long-standing extroverted friends.
Those persons I already know they share something in common with or may be of assistance in some shape or facet. That way I get credit for introductions and will always be the middle man/original source. They tend maintain and keep up the friendship or connection independently. My friends and associates tend to eventually become friends/associates with each other. Meanwhile, I'm usually nowhere to be found.
But I know everything is on good terms so I can always utilize folks when I need it.