|Both my mother and my grandmother sewed garments for themselves and their families all their lives, as well as doing alterations for pay. I wish I had paid more attention when they were trying to explain things to me. :-)
Going through my mother's things after she passed away, I discovered my grandmother's sewing box that she had saved and inside was an example of the most amazing efficiency. At the end of a project, my grandmother would gather up the unused bottons and string them through a safety pin. This way, they all stayed together. Sometimes she had to bend the pin a little to accomodate the diameter of the bottons.
I'm going to start doing this too. Keeping them on the paper cards they came on takes up too much space. And just dumping the loose buttons in a can or box makes it really difficult to find all the matchs when you need them.
Hope this helps someone.