I typically spend a week with one headphone, then change it to another for another week. I mostly work from home so I can cycle them but I think that after listening to one set of cans for some time you need a bit of time to adjust to the new sound so giving them a week seems fair. Also, I can appreciate sound differences more as well as other nuances like build or comfort. I do not have any order specified, I just pick one at the beginning of the week, usually one that I haven't used for a while and also something different enough from the one I was using prior.