Some people argue that higher-order thinking like critical thinking uses too much resources of human mind and it could be inefficient to use critical thinking every time. It may be true because critical thinking uses slower processes of human mind and in some situations you may have to make very fast decisions.
One of the solutions is to train a skill to quickly decide do you need to begin thinking critically or you can use a fast automatic response. It may be easier than you think, because even complicated mental processes, that require a lot of effort at first, can be optimized to use less and less during training and repeated applications.
So if you start use this approach you would apply critical thinking every time, but in the same time you would decide do you need more critical thinking or you can use some faster and simpler mental processes. Also as you use different critical thinking skills often, they would become easier and faster to use, consuming less mental resources. It means that if you spend some time and effort to learn critical thinking, it would take less time and effort to use in future. You probably noticed the same phenomena in other areas when you learn something.
With this approach we can answer the original question. You may use critical thinking as often as you need, the frequency will depend on your skills in critical thinking and other areas, and also on your dispositions. So when you face a problem you may first choose from a number of skills and approaches how to solve it better, on this stage you can use both critical thinking and any automatic processes and fast heuristics you have. Also after making each decision you can review it and take steps to improve this whole process in future.