I am using a late 2009 i7 iMac. I would like to get a laptop so that I can do some photo editing on the go and so that I have something portable if I attend workshops that require you to bring your own computer. I should emphasize, however, that most of the time I don't think I really need a laptop as I have an iPad Air for the more basic things and prefer to work on a larger monitor in any event. After looking at my options, I think I have decided to get a retina Macbook Pro, but I am uncertain about whether to get the 13 inch or 15. Based on my needs, I think the 13 inch should be fine in terms of power, but I wonder about the screen size for doing some editing -- even though most of the time I would be using a larger screen. My 3 questions are: (1) Is a 13 inch screen sufficient for some photo editing? Are others using a 13 inch or is the 15 really recommended? (2) Would the base 13 inch retina Macbook Pro (i5, 8 gig of ram) powerful enough for several years? I use Creative Cloud and plugins (NIK, Perfect effect, etc.), but am not a power user and photography is a hobby; or (3) Would I be better off just spending the money and going for the 15 inch (which has more memory and the i7 at base level, plus a larger screen) and then using that as a base with a larger monitor rather than buying both a 13 inch and eventually a new iMac to replace my late 2009 i7?