I bought my APEX classic controller back in 2014 used. To be honest I don’t know how old it was when I bought it. For a year it sat outside on plywood in back of my freshwater tank it ran my pumps, all my probes etc. I then bought a Saltwater tank and moved it inside my stand next to my sump and about six months after I did that I put a piece of plexiglas between it and the sump. Seven months ago I moved it out ( finally) to a outside cabinet mainly because a bought two Neptune Systems dosers and I knew I really needed too although it showed no rust or anything. Still running fine no issues. I have all modules
Except for the dissolved oxygen.
Last week I upgraded the controller to the 2016 but all modules are the same everything is still running.
I have had two issues with it in all this time. One was the external display that I accidentally cut the wire, bought another one ( used) and didn’t know I needed to upgrade the firmware.
Called support and they fixed it right away
Another issue was again the display and they login and they couldn’t fix it so we had to send it in. They fixed it and sent it in.
So new, used I don’t know. But there’s my story with a used at least five year old APEX Classic