The phones don’t require a “burn in.”

And don't buy either of these phones for listening via a smart phone or a laptop's 3.5mm headphone port as you will probably be disappointed with the results

These phones are easy to drive but deserve to be driven by first rate upstream components

Best head phones ever

And on page 1 of the Shure owner manual is a useful list of seven volume levels with the max allowable listening time to avoid hearing damage, from 90 dB (8 hours) to 115 dB (15 minutes) to 120 dB ("never").The differences between the Shure and Oppo are also noticeable when listening to movies and i prefer one phone over the other depending on what will be listened to (and viewed)

If you want a superb design, comfort and sound, I can recommend they phones without reservation.

These are also some the the most comfortable phones I’ve worn.

These are very comfortable phones; light weight; roomy earcups; low clamping pressure