Supply limits how many support structures and units a commander can field at once. Each team has a flat cap of 200 supply. Placing something that uses supply fails if it would go over the cap; destroying or recycling it frees the supply.
What uses supply#
| Marines | Supply | Aliens | Supply |
|---|---|---|---|
 MAC | 15 |  Drifter | 5 |
 ARC | 25 |  Whip | 30 |
 Sentry | 15 |  Crag | 20 |
 Sentry Battery | 25 |  Shade | 20 |
 Observatory | 25 |  Shift | 20 |
 Robotics Factory | 10 | ||
 Armory | 5 |
Infantry Portals (0), Phase Gates (0), resource towers, chambers and hives do not use supply.
In practice#
200 supply is a lot early on and becomes a real limit late: for example 5 ARCs (125) + 4 MACs (60) + 2 observatories (50) already uses 235. Recycle what you no longer need.