I used to stick some music on and think "I wonder what this sounds like on my Q701's" and play a couple of tracks before moving on to something else. With the Senn's I just stick music on & forget about everything else. Whole albums go by, then it's time for bed.
I can also state for a fact that, while I've suspected it to be a factor in other past components, burn-in is absolutely essential to the 650's sound. I liked them from the get-go but they sound incredible after around 200 hours.
All this is via my ODAC/O2 combo.