From: St. Louis
More could be said about how supply is expended. Also, what is relevant to stock is greatly altered in DBB-C, which I believe ought to be the stock form. Let me try a list:
In the field, fortifying, repairing/expanding airfields, repairing/expanding ports, and repairing refineries/oil fields can soak up a lot of supply.
Repairing/expanding industry, both heavy and light can eat up a lot.
Industry includes aircraft/engine factories, both repair and production.
Many, many procedures cannot occur if there are not adequate supplies present. For instance, replacements will arrive quicker at well supplied units.
In DBB-C overstack consumes an incredible amount of supply, in both, fortifying to level 7-9 uses a very large amount of supply.
Attacking as well as defending eat up supply.
Creating torpedo inventories expend supply, as well as bombing campaigns and the like.
Bombardments, especially by the likes of BBs and CAs consume supplies.
I've just spent 5 minutes on this, much more can be said.