Mean time between failure (MTBF) figures provide a way to compare indications for how long devices keep functioning as intended. There are two main standards MIL-HDBK-217K (a military grade standard assuming 24/7 usage) and Telcordia SR332 (a telecom standard). Non-industrial equipment typically uses Telcordia SR332 to calculate MTBF figures. This standard  which gives a 25-300% higher figure than MIL-HDBK-217K. 

Industrial switches and routers are fanless, i.e. no moving parts. As a result, a non-industrial switch typically operates 5-7 years, compared to an industrial switch which is created to be functioning 15-20 years.

Finally, electromagnetic interference (EMI) in industrial environments can cause communication challenges. Industrial equipment is designed to be able to withstand these disturbances to a much larger degree. 

Since commercial network components do not fulfill the same requirements as industrial, commercial equipment is typically possible to source at a lower initial cost. 

In addition to effect availability, the need to replace commercial equipment more often drives maintenance cost. Of course, new equipment needs to be sourced once old fail, but in addition the new equipment needs to be physically installed and configured.

Using industrial equipment in industrial applications may not result in the lowest initial up front cost. However, over the course of a system’s lifecycle there will be many factors contributing to a lower total cost of ownership. But most importantly, it will keep your system running!