Exactly this. There are many cheap (I mean cheap, not merely inexpensive) versions of "industrial" electronics on eBay. Most of them will probably work just fine in an office environment at room temperature. But put them in a factory where the temperature near the doors in winter can be below freezing and up near the roof in the middle of summer it's well over 100F, then your cheap eBay-purchased sequencing timer starts having hiccups, dumping hot asphalt on the floor.