Standard practice should be to warm it up in the ON state, otherwise it won't really warm up properly because much of the electronics are turned off. I leave mine in the ON state 24/7/365; that was standard practice for analytical instruments , including scales, in the laboratories I worked in. I was a system engineer for a major instrument manufacturer, and their systems were designed to be on continuously with the exception of light sources.Note that it doesn't clarify whether warmup is performed in standby (as implied in the Assembling section) or with the scale actually turned on.