Developing iOS or OSX apps requires installation of XCode. For better or worse, Apple releases new Beta builds of this software fairly rapidly. For most purposes, it might suit you to simply wait for the official upgrade to come. However, if your use case is in learning something like Swift 2.0 then you would need to keep downloading new Beta versions or else you might be out of sync with new features/ resolved errors etc.
Unlike other apps, it is not possible to simply press an ‘update’ button and get your Xcode upgraded. The catch is that all Beta versions of Xcode are independent of each other and if you want to, say upgrade from Xcode 7 Beta 3 to Xcode 7 Beta 5, then you have to download the newer version and move the older one to trash (or you could continue to use it as well). There – simple once you know it!
Oh, and these are fairly hefty downloads (3-4 GB) so you might want to keep that in mind.