What are some good ways to free up disk space on OS X >= Yosemite?
More Suggestive answer supporting with everyone's answer as our main purpose is to delete unnecessary file and folder for iOS developer: 


DeviceSupport - You can keep the simualator which log's you may need in future. It's actually symbolicate crash logs for different device/iOS. 
Delete this folder after every few days interval

~/Library/Developer/Xcode/DerivedData
All your targets are kept in archived form in Archives folder. Before you decide to delete contents of this folder, here is a warning - if you want to be able to debug deployed versions of your App, you shouldn’t delete the archives 

~/Library/Developer/Xcode/Archives
iOS Device Support folder creates a subfolder with the device version as identifier when you attach the device. Most of the time it’s just old stuff. Keep the latest version and rest of them can be deleted (if you don’t have an app that runs on 5.1.1, there’s no reason to keep the 5.1.1 directory/directories). 

~/Library/Developer/Xcode/iOS DeviceSupport
Core Simulator folder is familiar for many Xcode users. It’s simulator’s territory; thats where it stores app data.   It’s obvious that you can toss the older version simulator folder/folders if you no longer support your apps for those versions. And, it’s safer to use ‘Reset content and Settings’ option from menu to delete all of your app data in a Simulator. 

~/Library/Developer/CoreSimulator 
Caches are always safe to delete since they will be recreated as necessary. This isn’t a directory, it’s a file of kind Xcode Project. Delete away! 

~/Library/Caches/com.apple.dt.Xcode
Additionally, Apple iOS device automatically syncs specific files and settings to your Mac every time they are connected to your Mac machine. To be on safer side, it’s wise to use Devices pane of iTunes preferences to delete older backups; you should be retaining your most recent back-ups off course.   

~/Library/Application Support/MobileSync/Backup


i got back about 40GB! For more help go to: http://ajithrnayak.com/post/95441624221/xcode-users-can-free-up-space-on-your-mac