>>9991797As a kid, I loved my LEGO boxes. I was mostly into Creator, so I used them to store the pieces to each set. That way, I could pull a box off of the shelf, flip open the lid, and build wherever. I also repurposed the boxes from bigger sets with tape in order to store my collection and then take some of it with me on the go. However, my favorite ones were definitely X-Pods and BIONICLE canisters because they were more durable. And those blue LEGO tubs were also fantastic for building walls. Because of these methods, I still have many of them to this day.
As an adult, I don't have as much use for them because I sort my pieces now, but I still think they're nice to look at. One way or another, everything in my childhood collection ended up taken apart and dumped into clear plastic totes, and I have yet to put them back together. They're currently safe in storage for the promised day, but I can't say the same for all of the cardboard boxes that weren't being used anymore.
Although there are ones from my childhood that I wish I had kept, and others that I can't believe that I didn't recycle, it ultimately boils down to preference. Of the boxes that I didn't immediately recycle as an adult, I kept all 4 of the NINJAGO: Master of the Mountain wave boxes for the board game sets so that I could store them like my LEGO Games sets, and any that I couldn't decide if I would want to resell the set down the road or not. At the end of the day, I'd at least like to look at the box for 71741 NINJAGO City Gardens and then decide from there.