What happens when I use up all my upload units?

It depends on what plan you are currently on. Any of the paid plans will continue service without interruptions, and you will be billed proportionally to how much resource is used over the set limit. See our pricing page to learn more. The free plan has hard limits, which means that your uploads are blocked until the end of the billing cycle when your credits are replenished, or until the upgrade to a paid plan.