For the slightly used blades I wrap a small piece of painter's tape on them and slip them back in the plastic pouch they come in. I keep my blades in a plastic storage box divided in compartments for each type blade and keep the blades in the pouch they come in.. On top of the blades is the red pouch (now empty) that Mike sent his sample pack in. When I am cutting I place the pack of blades I am using from on top of the red pouch and close and secure the lid on the box. Secure the lid on the box?, Yes, cause when I knocked the box over and spent lots of time re-sorting the packs I learned to secure the lid.
When I need new blade, open up, pick up pouch on top and get new blade. I keep a few used blades on magnet stuck to box fan next to saw. These come in handy to pull out that stubborn saw dust that sometimes wants to stay in the cut. Also good to remove small slivers or pieces that want to stay in the cut. Also great to add a dab of glue under pattern when piece wants to lift up. Also good to pull out the excess glue from cut when too much of a dab was used - I am probably the only one that uses too much of a dab though.
Some times, not often, but some times I have changed to a new blade when just a little more cutting was needed to finish. This new blade still has some life in it, and when the next project will use another size or type blade, I put the painter's tape on the blade and place it back in the pouch with the new ones. Next time I need that type blade, I take out the one with the tape. Should never have more than one taped blade in pouch at any time.