Ok, so I need a new fax. The answer is you should if your volume is going to be less than 10 pages sent or received per day. Let me explain some differences. Store-bought units use modified Huffman as a compression code. If there is heavy long distance, then a 14.4 bps modem should also be considered, or at least it should be able to be added on at a later date.
Commercial units have a metal chassis to prevent flexing of the unit.
Store bought units have no chassis. Commercial units should have the ability to grow with your business. Heavily used store bought units do not hold up over time They use inexpensive nylon gears that wear with heavy usage. We know, we service them. This is always something to be concerned about.