I guess Paul B won the trophy alread... .lol
Anyways, children: one of my 100 watt Supreme heaters from 1970 is currently on my 31 Fiji AIO. My lfs owner looked at me funny when I told him I had an old Supreme heater from way back when. 3 months and still heating!
I do have some equipment running since 2007-2008... (13+ years).
My Bubble King Supermarine 250 skimmer. Still one of the best skimmers money can buy! I did need to replace the pump a few years ago, so it might not count?
I also have a couple of Tunze 6101 stream pumps from the same time on my fowlr. This is the old boxy shaped pumps (the last generation before they got the rund shape). I've modified the plastic gills of these and they now both provide a ton of flow and go forever between cleaning. I still need to find a worthy stream pump model the day these stop spinning. I bet these can blow the flesh from any coral unlucky to placed in front of it (its on a fowlr system) ;-)
150G & 65G 2015 start up. Waveline 10000II return pump, Mag drive 9 return pump, Kessil 360s, Kessil AP700, Tunze 6055s and 6095s circulation pumps. I rate all these as "TANKS" they just will not break. I would have added APEX Gold system, But it had a brain dump a few weeks back and had to be replaced.