Quality is the biggest reason. Print services generally use commercial printers with finishes much better than the typical desktop printer. These services also offer post processing such as polishing or dying the parts with commercial grade equipment.

Owning a printer also means an upfront investment in equipment and supplies. Much like computers, the technology is improving quickly, so in a few years your system may be outdated and you'll want to purchase a new one. With a print service, somebody else is investing their money, so you just have to pay for the finished parts.

Print services offer a range of materials and finishes for each material, ranging from metal to plastic and ceramics. Each of these materials has its own set of equipment to maintain and supplies to have on hand, which is too costly for an individual.

Consumer printers have a high learning curve compared to commercial printers. Desktop printers, especially those built from kits, are notoriously hard to maintain. To get good prints, printers need to be calibrated correctly, a time-consuming process.

Although not for everyone, building a printer from a kit of parts holds outstanding educational value in learning how electromechanical systems work and how to maintain your printer.

There are two major advantages to owning a printer, time being the big one. If you're developing a product, your cycle will move fastest if you have a printer in your office. You can walk over in a few hours and pick up your print rather than waiting several days or weeks to receive a part in the mail.

If you have enough print volume, the overall part cost is also going to be as much as 95 percent cheaper on your desktop printer. Commercial machines are expensive to operate, and when you buy parts from a print service, you're paying for the cost of the printer as well as human labor to make that part.