I was thinking more and more about this so called "memory box" and thought, it would be useful for it to accomodate both old and new pictures, as to stimulate maybe some old memories that you had with this particular friend/relative but then at the same time still interesting to see in the new pictures how they have changed. So instead of just having up-to-date pictures I think it would be a good idea to consider a mixture and if this was the case I think the box would have alot more sentimental value added to it.
The reason I say this, is as I look back at all the photographs I have taken over the years, it makes me feel as shakespear once said "such sweet sorrow". To me, this signify's a good feeling and I think others will agree as looking at your previous years can sometimes bring a warm feeling to your heart. Yet your heart may be weighted down to some degree thinking of what has been that might not ever be again. So I think it would be a good thing for owners of these "memory boxes" to be able to reflect upon such things.