There are a variety of opinions on how to judge convergence. The level of convergence required depends on the purpose of the simulation (whether qualitative or quantitative results are required) and the details of model. In general, you need to consider residual size (both RMS and MAX) and overall flow balances (conservation). Some cases, such as those with transient convergence behavior, require other considerations.
When quantitative accuracy is required, it is highly recommended that you test sensitivity of relative quantities (derived quantities) to the convergence target. These can be monitored during the run in the CFX-Solver Manager using monitor points.
Important: You should always check whether your run stopped because your convergence criteria were met or because the maximum number of iterations was reached.