After having spent my time working for a robot company and dealing with the "used" and "obsolete" robot issue, I have formed these opinions:
- The mechanical bits, if maintained well, will last a long time. I describe "ong time" = 7 or more years, but certainly could be more.
- The control components have a realistic lifetime of 5 years in operation. The computer components become obsolete through supercession of newer technology; the software (think Windows' string of new versions) becomes obsolete; power components age because they're handling all those watts being pushed through them.
- The company accountants assign capital asset depreciation schedules of 20 years to systems with robots. This is completely unrealistic, but forces operations to keep those arms deployed and on the books.
- The robot companies are pressured by the sales force to "support our customers" and keep supporting aging & obsolete products and software.
- Then you get the company behavior & policies to force retirement of older equipment. Fanuc's policy is one extreme example. Usually repair parts simply run out of inventory and support becomes impossible or prohibitively expensive.
- And finally, entrepreneurs will try to continue supporting obsolete equipment because they perceive a market niche and a chance to make money.