You add value in three ways:
1) You provide a unique skill they lack.
2) You give money.
3) You introduce someone who can potentially help them with their business or personal life via the first two points.
The harsh truth:
Most of your relationships do not have any of these or at least, after growing up, you'll realize that they don't.
You and your friends or family only hang on due to memories or altruism.
But people get tired.
That's when friends start to take each other for granted.
That's when things get sour.
That's when you realize, "Wow, my friends/family are pretty useless. I actually really don't want them around anymore."
That's when a fallout will happen. You'll lose people in your life.
Sounds harsh, but it's the truth.
The best thing you can do is give back whenever you can and also to watch out for yourself.