Supply?

[Pizzaspy]

In games without advanced supply, I have this vague sense of supplies effects, and use the repair screen to get a vague sense of how Im doing with supply, but is there any way to actually track it moment to moment?

[Scott_WAR]

You mean see how many supply you have left in your supply pool? If so, left click on a territory you own and you will see a box on the right side of the screen. The number in the box at the top of this menu is how many supply you have in your supply pool

[von_Schmidt]

As Scott_WAR stated, if you select one of your units, a popup window will show the available supply - and as soon as you move the unit, the supply will decrease appropriately.

Also, if you press 'U' (or the relevant icon at the top of the screen) you will see where on the map your supplies are located.
This is very handy to trace the unused supply trucks moved by the computer towards your units or towards a repaired factory/resource without actually arriving there to be used up. That happens sometime, unfortunately.
Extra annoying if the supply gets stuck on a transport, which will stop the TRN from moving this turn and the next turn!

As the WA, my final action during the movement phase is to zoom out to max (using the modded map parameters, showing approx 1/4 of the map), hit U and check for any stray supply.

(edit: the above observations probably don't hold if you are not using advanced supply. Give that setting a shot as soon as you're reasonably comfortable with the game - it adds a real layer to the game and top your decision-making).
- von Schmidt