Each event you go to you can either get Build Cap or Build Blanket. Blanket is an amount of experience you receive for roleplaying, fighting, and just plain living through another event. Cap is the maximum build you can earn per month, and is one build more than blanket. If you want Build Cap, you must pay Eeps to "Cap Out."

As you advance in level, it takes more and more Eeps to equal one build point. This makes it harder and harder for you to cap out, but you will always get blanket, just for showing up and playing your character. Most people find it worthwhile to cap out their first few events, while it's still cheap, but take blanket after that. You can also earn build with Goblin Points, the credits you receive for working for SOLAR. The Goblin Point conversion is the same as Eeps, except it tops out at 30:1. No matter what level your character is, they can always buy build points for 30 Goblin Points.