I have 256 GB SSD in my Macbook Pro, I have no external disks, and no cloud storage other than a Dropbox's free tier. So I think it's fair to say that I'm not a data hoarder. I live my digital life, much like I live my real life, lean and light.
In the last few months I've been constantly hovering around ~8GB of available space, and more recently I've opened my Macbook to messages of "No available disk space". Considering that I dilligently manage my storage I've been a little confused as to why this is the case.
After digging around a little, I discovered that the ~/Library/Developer folder is weighing in at 35.75GB, thats 13% of my disk space!
Digging a little deeper, ~/Library/Developer/Xcode/iOS DeviceSupport/ contains the symbols for every iOS version that you've connected to your machine. If you are like me, and have been doing development for a while, you'll probably have a few, I had 12, going as far back as 7.1.2. They range in size from 600MB, all the way upto 3.36 GB. For my development needs I only need the last two versions; 9.2 & 8.4.1. Removing the unused symbols, as well some dervived data from some old projects helped me recover around 13GB.
If you've installed Xcode Betas you may have had the issue where you have duplicate simulators, sometimes even 3 copies. Each simulator is usually 1GB+ so removing excess ones can save you some additional space. On the advice of this stackoverflow post I installed the snapshot tool, which is part of the fastlane toolkit. It has a handy command called "reset_simulators" which will remove all the simulators, and recreate only the simulators for the current primary SDK you have installed.
The above tips helped me recover 22 GB just from Xcode.