My closest friends are the ones I've known for years - my best friend dates back to primary school and my other closest friends, I've known for 28, 26 and 10 years respectively. I've found it harder to develop close friendships as I've grown older, but the strongest ones have come about through voluntary work - there is something about working together to benefit a cause you both feel strongly about that forges close links. And you also tend to see each other at your best & worst and support each other through the highs and lows of the project, which I suppose mimics the ups and downs of our younger selves! I volunteered 2 years ago with a group that did a week-long series of events to benefit the local community and became friends with one of the organisers - earlier this year, we were involved in another week of events, and I would say that now, she is almost as close a friend as some of the ones from my younger days. I've also made another good friend through volunteer work for homeless and refugees. And if you build a friendship over a shared cause, you never run out of stuff to talk about!