Corps vs Armies?

[mdsmall]

What's the general wisdom on the cost/benefits of buying new infantry corps versus infantry armies for Major Powers? And the cost/benefit of upgrading armies mobility from 3 to 4 AP? If you don't upgrade the mobility of infantry armies, what's the best way to use them?

I am playing Axis in the 1939 campaign for the first time in a PBEM game and expect to be faced with these choices in the near future.

[Platoonist]

Corps have that one additional AP and thus move faster and aren't much inferior than armies on defense, but are much less effective than Armies on the attack. Armies tend to plod into battle, but make better overall assault units. They also defend better against aircraft. Corps are roughly 100 MPP cheaper on average.

Mobility is rather expensive and you have to take care on how you dispense it. Armies are especially costly to upgrade. I recall in one of my first games happily and mindlessly going around and upgrading the mobility of all my armies, and then discovering I had run out of MPPs for anything else that turn after upgrading just four. For the Germans you might want to consider adding mobility only for your more elite corps and armies as it seems there is always some other pressing need screaming for those points. I do add mobility to most Allied units, as they often seem to have the MPPs to burn. They really make the Soviet infantry dangerous in the late game.

[ThunderLizard11]

Corp are more for holding ground rather than attacking. I usually never order new armies but there is a steep discount to replacing major armies and corps destroyed. As Axis, I use my MPP for tanks and TBs and MBs. As Allies, I focus on SFs and armor as well as planes. Spend on mobility sparingly but having a few mobile units is helpful as Axis for rapid breakthroughs in Barbarosa.