Spot instances offer significant cost savings, up to 90% lower than on-demand rates, but are often avoided due to concerns about fault tolerance and availability. Automation plays a crucial role in enabling teams to run fault-tolerant clusters on spot instances, reducing cloud costs for Kubernetes users. The key challenges of spot instances include the brief window of time available to replace a reclaimed instance, bidding process risks, and provider capacity limitations. Automation tools can mitigate these challenges by automating spot instance provisioning and termination, providing fallback to on-demand resources when needed, and allowing partial utilization of spot instances with configuration control. By embracing automation, teams can build fault tolerance into their clusters while reducing costs, with CAST AI clients saving an average of 63% on their Kubernetes bills.