Although I had already used multiple plays of the 74 minute PAD CD-R for burn-in, there was a rather dramatic further improvement with the dedicated machine burn-in from George Saubon of cableburner.com for two sets of Marigo analog interconnects.
My interconnects had been stored away for six months, and I cannot tell whether any previous factory, or PAD burn-in may have evaporated by the time I sent off to George for further professional burn-in.
I found the PAD CD-R seemed more effective than my Densen 3 minute break-in CD, even when playing the Densen over, and over, to accumulate same total burn-in time. However, it is hard to compare break-in products, unless a successor burn-in procedure seems to create a further improvement.
I am in the camp that believes simply playing components may never break them in fully, as buying used equipment on Audiogon never prevented attaining further audible improved performance with any of the dedicated break-in ideas mentioned above.
Most recently, I have become a fan of Lloyd Walker's SST contact enhancer, which upgrades the listening experience still further, within seconds of being applied to any metal signal, or power, contact points in my systems.
It is fascinating to hear upgraded sound just by optimizing components, and wiring, rather than having to replace.