Of course there's the saying: To have a friend you must be a friend.
I look back on my life and now, in my late 70s and I can see numerous stages where I had varying levels of "friendship": School boy, college student, young married, married with children, professional career, grand father, partially retired and late in life second effort as a writer, fully retired from the cares of working for a living and having time to pursue new fields from the comfort of my couch. Each period had different challenges to happiness and pursuing friendships.
I'd like to discuss this further, but I need to catch some lunch before the Sunday EpicrueanFriends zoom.