From: Utlima Thule
I'm trying to understand how pool works in the game and I have many questions, where can I find a guide explaining how game works?
My way of understanding production is to split into two big blocks. In the first are the outputs of named and specialist factories and in the second are the things built with the generic armament points.
In the first, production is set, the factory exists, at a certain level and all things being equal (ie you have enough supply to underpin your industry and the factory is not damaged) a fixed stock (tanks, planes some vehicles) will appear each turn. This production is then taken into your units to fill out the TOEs or left in reserve to replace losses (ie the 'pool'). So for the Soviets in a quiet period you'll see masses of T-34s and T-60/70s in the 'pool' - you will need them to keep your combat units up to strength when you are actually fighting.
The second, production is on demand. Others could offer the detail, but in essence the AI looks at the list of equipment you need (ie are required to fill out your TOEs) and allocates the available arm pts. For the Axis there is not much you can do, since you don't raise units, in effect it is responding to fluctations in your TOEs (as the game progresses) and replacing losses. You may want to scrap some units just to avoid additional production as the game goes on.
For the Soviets its a bit more complex. Some lines do not get produced if there is no need, so no pool appears. Others seem to be produced on a regular basis, or you have massive pre-war stocks (ie a pre-existing pool - a lot of the Soviet howitzers were WW1 vintage). That means in terms of raising new support units you may choose to build those that are already in the 'pool' (ie filling out that unit will not cost additional arms pts) or something new. An example in my current game is that I am building a number of heavy AT support units (which require fresh built 107mm guns) but I'm also scrapping AT SUs that use the 45mm (these go back into the pool and are required by my divisional TOEs).
So its worth thinking about using up your pools against gaining a desired unit.