Its very much up to you how many to complete. Make a list of the firms that you would like to work for, listing the aspects you find appealing about each one. Rank them according to preference and this will give you a clear picture of where to start focusing your efforts. Start by taking the first five firms and looking at their application forms. Each form will take 2-3 hours to complete, so youll need to set aside a considerable amount of time. This will be in addition to any studying you may be doing, so dont underestimate how long the process will take. Its best to start with a small number and really focus on the questions, structuring your answers and ensuring your forms are free from errors. Submit these as far away from the deadline as possible, that way you can see what the feedback might be from your applications and then either your applications will be taken forward, or if rejected, you have time to alter the answers to your questions accordingly. If these applications are unsuccessful, you may want to start working your way down your list, completing more application forms in line with your preferences and the time you have available. Its far better to submit fewer forms of better quality than to apply for more and not spend as much time on the applications. Quality not quantity is definitely the key message.