Just to check, I presume the army supply costs or rather their resource needs are given as daily figures.
I was doing some (literally) back of envelope calculations and I reckon it only takes Infantry about 80 days at at 100% slider to equal their build cost, so 160 days at 50%. And that's in 1936. Build costs remain the same, while supply costs only go up.
Units have a deterrence effect on the AI I believe, but if you don't need deterrence and you're not using them it seems best to get rid of units and rebuild for war.
I was doing some (literally) back of envelope calculations and I reckon it only takes Infantry about 80 days at at 100% slider to equal their build cost, so 160 days at 50%. And that's in 1936. Build costs remain the same, while supply costs only go up.
Units have a deterrence effect on the AI I believe, but if you don't need deterrence and you're not using them it seems best to get rid of units and rebuild for war.