I am finally migrating from my cMP to my MacBook Pro and I notice I have pretty much zero space left on the main drive (512GB) after Photos went on it (175GB) - I presume I can have that externally but what is the best way do you think ? A USB stick or a drive as I would like access to it when I am out and about but dont really need all of it then, like maybe the last year or so or is that getting complicated ?