Depends on what you mean by "perfect". When it comes functionality, its a relative term as there are virtually no "perfect" devices, functions, transformations, products, processes. Regarding "burn-in", many different classes of audio components require what is colloquially referrred to as "burn-in" or "run-in" to provide optimal functionality, performance, and sound quality including headphone and loudspeaker drive units, cables, tubes, stereo cartridge cantilevers, and electronic components. Loudspeakers, cables and electronics usually require the most "burn-in" or "running-in" with respect to loudspeaker drivers. In electronics, and cables, it is usually the capacitors and other components or materials that take time to burn-in, and depending on the number and types (composition) of those components or materials will determine the time it states for them to fully burn-in. For dielectrics, the burn-in time often correlates to the dielectric constant of the material, the higher the dielectric constant, the longer it takes. For example, for film capacitors, the burn-in times are, from shortest to longest: polystyrene>>polypropylene>>>>>Teflon. For cables, it is usually the composition of insulating materials (which are also dielectrics) e.g. foamed polyethylene or FEP that determines the time that cables take to "burn in". Regarding the burn-in time for Yggy, I refer you to Robert Harley's recent review in TAS: Schiit Audio Yggdrasil DAC. Yggy has a LOT of components, which directly correlates to it's burn-in time... "Listening Although Moffatt warned me that the Yggy wouldn’t sound good right out of the box, I gave it a quick listen anyway after an hour of warm-up. He was right; the Yggy was hard, bright, forward, and flat. I checked in with it a couple of times over the next week and heard it improving somewhat, but it was still disappointing. I decided to let it sit in my rack, powered up, for a full month before revisiting it."