Apex governors and namespaces
Platform governors prevent any one execution context from consuming excessive resources on the service, which could be detrimental to its users. Overall, an execution context cannot exceed 10 minutes, though within an execution context, in practice, other limits would likely be reached before this.
For example, Apex code units executing within an execution context can only collectively execute for a maximum of 10 or 60 seconds depending on the context. Over the years, Salesforce has worked hard to consolidate what was once a confusing array of governors, which also varied based on a number of Apex code contexts. Thankfully, these days, governors are much easier to follow, and vary only based on the context, being interactive or batch (asynchronous).