Next to the interconnects and speaker cables, this is a topic with wast opinions and debate. Given that, and my many years of going through hundreds of components and systems, I generally take the folks who have all in or all out opinions with a grain of salt. Last year I did a seven dac shootout, and I followed the same pro ess. I hook up the new component, let it run for 1 hour and then I take the same reference songs and listen to it for an hour and take copious notes regarding fairly standard audiophile parameters. I quit listening for 50 hours and then listen again, and take notes about those same parameters. I rinse an repeat at 100 hours and then again at 200 hours. I have four systems, with each system have both a tube path and a solid state path. The large system shares a pair of Estelon X Diamond Mk 2's and the small system uses Joseph Audio bookshelf speakers. This took several months. A lot of work, and money, but Iearned a lot about many things. All systems changed after the break-in period. Some changed more than others. I am an Electrical Engineer, so I am pretty disciplined and detailed oriented:-) I have done this with many other components besides dacs. I think, next to dacs, power amps change the most.