In Japan the seventh anniversary of someone's death is considered a milestone. They call in a priest and have him recite sutras in front of the family altar. It's called a houji. In my family we mourn individually.
I visit Kate's grave almost everytime I go back to NH. Last summer I snapped off the branches of a tree that was growing through the chainlink fence next to her grave and dropped leaves and crud on her stone. Even now, seven years later, I can never quite recall the exact date that she died. I check the stone everytime but it doesn't stick.
I remember that I brought the last picture I had of her to the funeral. It was a picture of her, Mom, Stef and me taken at Mom's house a couple of months before. I'm not sure why I brought it with me, maybe I was planning to put it on top of her casket. But Dad said he didn't even have a recent picture of her so I gave the picture to him instead.