Checkly's engineers share practical monitoring tips from their experience in the context of service-level agreements (SLAs) and availability guarantees with large customers. To prove uptime, teams must ensure their services are available for the agreed-upon time, which requires frequent SLA reports and careful frequency selection for monitoring. The choice of frequency significantly impacts the measurable availability, with higher frequencies allowing for more accurate detection of issues and compliance with SLA requirements, such as four nines (99.99%) or five nines (99.999%) availability. By selecting the right frequency, teams can ensure their services meet customer expectations and maintain a high level of uptime.