I just recently downloaded the Android SDK. Downloading all the packages in the SDK Manager will take way too much time. So I\'m wondering whether I should deselect all the plat
No, You don't need to install everything.
Install the "SDK Platform" for the Android versions you've set as minimum, target, and in-between the minimum & target.
Examples:
Target API 23, Minimum API 23
Target API 23, Minimum API 15
Extras
The Android SDK Extras are usually not required; but it is useful to be aware of them since they may be required depending on your use case.