What term is used to describe whether a service will meet availability, capacity and security requirements?

Identify the missing word(s) in the following sentence.
The service desk should be the entry point and single point of contact for the [?] with all of its users.

Why should a service level manager carry out regular service reviews?

Which guiding principle focuses on reducing costs and human errors?

A flaw in an application could cause a service to fail IT staff are actively analysing the application to try and understand what is going on. What is the correct name for this type of flaw?