✓ You should consider your individual air requirements and choose a size based on this.
✓ You will need to purchase a machine that has enough pressure to achieve the performance you require for your application and processes.
✓ You should consider how many hours a year you will require your compressor to operate, if you need a constant or intermittent supply of air, and if there is ever going to be a fluctuation in demand.
✓ You may consider asking a professional to conduct an air audit for your facility or production line.