Rich Stump of FATHOM, a highly experienced Stratasys (NASDAQ:SSYS) reseller and 3-D printing service center has Stratasys printers in its fleet that have been in service for 15 years. From an investor perspective, well-built and still-relevant printers give Stratasys a great opportunity to generate an extremely long recurring revenue stream of highly profitable consumable material sales.

Interestingly, in Stump's experience, long life cycles haven't prevented firms from upgrading to new systems in as little as two years, as new materials and capabilities come out that better suit their needs. Stratasys' new Objet Connex3 is the type of 3-D printer that gets customers excited because it's the world's first multi-material, full-color, 3-D printer. In other words, it seems that product innovation will continue to keep 3-D printing customers interested for the foreseeable future.

In the following video, 3-D printing analyst Steve Heller sits down with Rich Stump to discuss the life cycles of Stratasys 3-D printers, what factors tend to influence future unit sales, and a 3-D printing advancement he'd love to get his hands on if it were available today. Going forward, Stratasys investors should be encouraged that product innovation continues to drive sales, because as more advanced 3-D printing systems are developed, it's entirely possible that the materials that come along with them will command even higher profit margins for Stratasys.

Steve Heller has no position in any stocks mentioned. The Motley Fool recommends Stratasys. The Motley Fool owns shares of Stratasys. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.