One never knows when life will change in an instant. Have you preserved or shared pictures and images of items you have that cannot be replaced? Don’t wait. A sudden illness, natural disaster, or other event can alter your plans for “doing it later.” Make certain others have digital copies of items you have. Initially focus on those items that are unique–letters, pictures, etc.
You can wait to make copies of census records and other items that are probably elsewhere.
But that wedding book that has signatures of relatives? That scrapbook that has one-of-a-kind pictures? Those are the things you need to focus on initially.
Life has a way of happening and those left behind may not have the interest in the things that you do.