If i'm going on a long ride I often carry two spare tubes, one of which is always a new one. If I'm just off on a shorter ride I only take a one spare tube which is always a new one.
The punctured tube gets taken home and slung in a pile. I tend to have a tube patching blitz, repairing 4-5 of them at once, when there's nothing on the TV one evening.
After repairing the tubes I inflate them then hang them up in the coat cupboard. If the tubes are still inflated a week or so later they get folded up and stuck in my saddle bag as spares. However, if they've gone down in this period then they get slung.