Workload is a metric that measures the work done by Bubble to power an app, quantifying activities such as database operations, workflows, and web interactions. Most apps will have sufficient workload included in their plan, but if needed, users can subscribe to discounted workload tiers or pay-as-you-go overages at $0.30/1,000 WU. To choose the most cost-effective subscription, users should first select a plan based on features needed, then add an additional workload tier if necessary, considering break-even points between tiers. Users can also opt for a workload cap to prevent overages and receive email notifications as they approach their workload limit. Assessing workload needs is crucial, especially when scaling an app, and tools are being developed to help quantify needs; users can start by using the Free plan or Starter plan to gauge their workload usage.