Cost, pure and simple. If tubes are involved, the catch would be that 'used' would need to be put into the spec's.
With exception of speakers, the 'burn in' is a myth to get you into the rituals of the hobby. Double blind test, the only true way of telling, has proved time and time again it is not necessary.
With exception of speakers, the 'burn in' is a myth to get you into the rituals of the hobby. Double blind test, the only true way of telling, has proved time and time again it is not necessary.