SLOs are well-defined, concrete targets for system availability. They represent a dividing line between user happiness and unhappiness, and they frame all discussions about whether the system is running reliably as perceived by users. The SLO Adoption and Usage Survey reveal that, despite the importance of SLOs in ensuring the reliability of services, many organizations have not implemented SLOs. The survey also shows that organizations using SLOs fail to update them regularly as their businesses evolve. These missed opportunities can keep organizations from gaining all of the benefits SRE offers.
It's because defining SLOs is a difficult task and many do not know where to start. In addition, our experience with customers suggests that teams may lack executive support, a critical component in SLO definition, alignment, and success.
This blog from the Google Cloud SRE & DevOps blogs explain a step-by-step guide for building SLOs and describes how to apply them to error budgets. So that your organization can use this data to make business decisions that drive feature release velocity that is in balance with the availability appropriate for your business and customer needs.
Read more at 
Google Cloud blog
