I've known my closest friend for 31 years now. We met when we worked in the same place. The friendship is very strong, and I know I could tell her anything. She is around the same age as me. I also have a good friend who is 11 years older than I am, and I've known her for 26 years, again having met her at my workplace when I changed my job. Both of these women have the same sense of humour as I do - which is possibly what attracted us to each other! DH's close friend and he were born within 3 weeks of each other, 73 years ago, and are still really close, being able to share the memories of their whole lives.