When the idea that we live on in the memories of the people who liked us, means sth to you, I would keep them. Every time you stumble over their entry this memory gets reactivated. I think that is a nice thing.

My grandmother died 40 years ago and she told me, when I was very little, to fold the seems of the coffee filter before you put it in. Everytime I make coffee I think about her because of that.