So today, after 5 years of nonstop, everyday use, I decided it was time to take the plunge and unclog my 2012 rMBP's cooling system. Here's some photos I took and I hope you find it interesting. BEFORE As you can see, there's a lot of dust and gunk inside my beloved laptop. For five years of accumulation though, I'd honestly expected it to be worse! AFTER And there we go! What did I learn from this? The main dust buildup was definitely at the air intake slots (at the bottom left and right of the rMBP), and I think this was clogging the airflow the most. They were just completely saturated with dust. A lot of dust had also caught on the fins of the heatsink. (Some of the fins on my heatsink are slightly bent, if you look closely - I certainly didn't cause that... I wonder if it came like that from the factory. Any ideas?) Whilst covered with dust, the fans themselves didn't look as though they were clogged too badly. Have I noticed my laptop running cooler, and was it worth doing? YES Previously, opening up Photos.app and browsing around would turn the fans on, but after cleaning they remain silent and the laptop is cooler. The fans in general are a lot less prone to activation when doing intensive stuff (like Lightroom work), and once they do spin up, they take much less time to cool stuff down and turn off again than before! I haven't noticed an increase in performance yet, my rMBP is just as fast as it was before. I bet it runs better under extremely heavy loads after cleaning, but I haven't tested that yet. Anyway, I hope you found this somewhat interesting. If you've got a MacBook that you use heavily and you can see dust in the vents and notice that your fans come on more than they used to, then definitely think about getting a pentalobe screwdriver and giving it a careful dust removal.