What happens when you know someone for ten or fifteen or twenty years?
You get to know them through their lifespan.
Babies, who are toddlers, who become children, who become young adults.
Or young college people who get married and have their own children.
Or middle aged people who grow old gracefully (hopefully) before you.
Some things never change. Their smiles. The way their eyes twinkle. Their laughs.
Other things do change. Their impatience. Their ability to hear you better. Their view of you.
I have some cards that say: It takes a long time to grow an old friend.
It is true.
That's what makes them so valuable.