Stones that are used for healing and magic need to be cleansed and charged regularly. I think it's best to cleanse and charge a stone after any healing work; stones I use as part of my own ritual circles or for meditation can go a little longer, provided my environment is reasonably harmonious and clear.
There are many ways to cleanse and charge your stones. Purification is often done with incense or smudge stick smoke, or with water and salt. The cleansed stones are then often charged with moonlight, sunlight, reiki, or a witch's intentions. I frequently use some combination of these methods myself.
Every year I keep a piece of paper on my home altar and after November 1st, I write down the names of people who die during the course of the year. And by people, I mean the beings that touch my life in ways profound and/or familial.
Generally they are the names of folks I know or the loved ones of folks I know. Sometimes they are people that I don’t actually know but whose lives have intersected with mine. For example, Wangari Maathai went on the Samhain list because of her amazing work and because of my deep admiration for her courage and strength.