I guess I don't disagree in principal, but given how stuff is made these days, I don't expect a lot of things to last that long. Heck, I don't expect my laptop to last that long, lol.Well, all you've really got are a couple of sensors a readout and a small fan. Lasting over 36 months doesn't seem like much to ask, but obviously it is since they don't in my experience.
As I mentioned I'm using them to augment the Boveda's as I had with beads before I realized how good these things are. So far it has worked well in my foot locker humidor, especially since its for rest and not opened very often.
I'm a cabinetmaker by trade and have thought several times of building a good size armoire type humidor cabinet but I'm still of the belief I guess that's its simpler to have a long(ish) term storage unit that you leave shut as much as possible, them a medium size unit for sticks that are basically ready, combined with a desk top humidor that I smoke out of.
I also agree that one medium of storage should be for long term storage and another different medium for ready-to-go smokes. I'd love to have one huge cabinet (bigger than this one) just for long term aging, and then maybe use my small end table cabinet for ready-to-smoke use.