Macbook Pro 15" vs 13" - Performance vs portability Currently I've got a MacBook Pro 15" (mid-2010, model 6,2), with 8 GB RAM, 2,5 GHz i5 Processor and Intel HD Graphics 288 MB video card. Seeing as it's 5+ years old, I really need a new one, reliability wise. It freezes when I'm working and has it's random shut-downs/white screens/black screens. (Link to specs)

But, I've got a dilemma. I'm a graphic designer and need to work with Photoshop, Illustrator and Indesign, so performance is needed. BUT, I also am working on my masters degree, which requires portability, internet and MS Word (no more).   

I don't take on too many design projects seeing as getting my masters degree takes up a lot of my time. But, I do need to work with big Photoshop files (2+GB) which my current granny-macbook can't handle properly anymore. (specifically CPU and GPU are busy chewing on the size documents I work regularly on)

How can I evaluate my workload to better decide if 

Retina 13" with 3.1/3.4 dual-core Intel Core i7,
16 GB RAM, 512 GB SSD, Intel Iris Graphics 6100  

vs

Retina 15" 2.8/4.0 GHz quad-core Intel Core i7, 16 GB RAM, 512 GB SSD with
Intel Iris Pro Graphics + AMD Radeon R9 M370X with 2 GB vRAM

What do you recommend? Is the 13" performance OK to last roughly 2 years of heavy Photoshop use or do I need to get the bigger and thus less-portable 15"? Is the 3,1GHz dual core 13" as good as the 2,8GHz quad core 15", or at least a lot better than the one I have now?
Here's the way it goes in our household:

I own the 15" Model you describe above (albeit a slightly earlier version with the GTX750M GFX card) and my other half has the 13" you describe above (again, albeit 6 months old at this point)

Now, she does a lot of graphical work on it in Adobe CC - Photoshop, Illustrator, InDesign, etc - much the same as you want to. She says it never skips a beat for her, even when she's running it on external displays in the office and driving the graphics side of things hard. She sometimes gets frustrated with the lack of screen real estate compared to mine (when she does use it) but it's generally not a problem for her. The battery also performs a bit better, which helps if you're on the move a lot. Sure, a bit of extra power would help her but the portability and price trade offs aren't worth it.

Based on what you've said, I'd recommend the 13". It's plenty powerful for what you want, but I would use the left over cash to buy a couple of nice 24" external displays if you have the space to set up a small office. I love having 3 displays running (1 on the MacBook + 2 external.) Better on so many levels!

Another note - it used to be possible to upgrade MacBooks (more RAM, swap out the HDD for an SSD, etc) so I used to recommend buying less and adding to it when you need it. Can't do that anymore, so buy as high spec as you can afford.