Ever since my first visit to the Pick-A-Brick wall at the Lego Store, I've been an advocate of building inside the cup. That is, connecting the bricks together to use as much space as possible inside the diagonal-sided cup. But after my most recent visit at the beginning of May, as I was un-sticking around 200 green 4x4 plates from each other, my bloodied and scratched fingers begged the question "Just HOW MUCH more space am I saving by building inside the cup?" After all, building a good cup takes up a fair chunk of time at the store, and even more time at home to unstick all the bricks before sorting and putting them away. Is it really worth all that effort? Time to experiment!
I went to the Lego store armed with two large cups (50 cents off your refill!) and a small cup that wasn't going to be part of the experiment. I spent about 15-20 minutes building bricks together in one cup, taking time to fill in the extra space on the sides with vertical bricks, as can be seen in the pictures below. For the other cup, I simply dumped bricks in by the handful, doing nothing to conserve space other than shaking down the cup between handfuls of brick. For the sake of making the experiment simpler, I only used actual bricks, with the smallest pieces being 1x2s. No plates, no slopes, no miniature detail parts like levers or hinges. Once my large cups were ready, I filled the small cup, picked up set 40172 "Iconic Brick Calendar" and headed for home!
Upon reaching my workbench, I unpacked each large cup, keeping their parts entirely separate, and arranged the bricks in 8x8 squares for easier counting.
By building inside the cup, I managed to fit 266 more studs worth of brick versus the cup where I just dumped bricks in. 1,124 studs worth of brick over 858. That 266 studs works out to 33.25 2x4 bricks. Now, I had used mostly 2x2 bricks in the unbuilt cup because that's what I went to pick up in the first place. So what if I had tried to fill the cup with ONLY 2x4 bricks? To answer this question, I dunked an empty large PAB cup into my drawer of 2x4 bricks, and topped it off until I could just barely close the cup, as Lego store rules dictate. Then I dumped the 2x4 bricks out on the empty table and counted them out. I managed exactly 800 studs worth of brick, or 100 2x4 bricks total. This means I lost out on 40.5 additional 2x4 bricks if I had built inside the cup.
So, the first half of the answer is obvious: Yes, building inside the cup does in fact afford you more bricks than if you simply dump the bricks in. The second half of the question is harder to answer: is it worth it? While one wants to insist YES, consider the time. It takes a good 15-20 minutes to build inside a cup, versus 2-4 minutes to simply dump the bricks in. Then it also takes time at home to disconnect all the bricks from each other (my fingers still hurt from unsticking all the green 4x4 plates) before they're ready to be used. Many economists have put forth ways to calculate the value of one's time, but I say simply use the hourly wage you get paid at your job. Let's say you spent an hour total on building and unbuilding two cups worth of bricks (15 minutes to build each one, and 15 minutes to unbuild each one). You acquired 81 more 2x4 bricks by doing this. According to the Pick A Brick website, those 2x4 bricks are worth 20 cents apiece, or $16.20 more of bricks. Measured by volume, you acquired roughly 25% more bricks for the same cost of filling the cup. Is that extra brick volume really worth your time? I say yes, but perhaps others might say no.
All-in-all, I fully intend to continue building inside the cup. Even if I'm not gaining THAT much more brick by doing so, it means I get to spend more time at the Lego store among my fellow nerds. Plus, the added fun of building Lego in the first place! After all, isn't that what it's all about?