The volume of your tank may vary depending on the output pressure of the compressor you will buy and how much compressed air you demand at the same time.
Remember, the larger the capacity of the tank you buy, the longer the first fill will take. If you start your compressor before the factory working hours start so that the air in your tank is full and ready, it will be ready when the job starts. Therefore, you should consider this account in order to avoid unexpected delays in your work.
The larger the size of the air tanks, the more compressed air will be available for your operation. This will save your compressor from running if not needed and save energy. In other words, choosing the volume of your air tank large will reduce your electricity need.