Not at all. You just need to install those platforms which you are targeting for your apps and which you intend to test your app with. If I were you, I'd install:
- API 24 (Multiple app windows, Notification enhancements, Multi-locale support)
- API 23 (Runtime permissions toggling, Doze mode and BoringSSL)
- API 21 (Massive changes, including Material Design)
- API 19 (Many changes to various API methods)
- API 18 (New features such as BLE, new API methods)
- API 14 (Big overhaul - addressed several issues in Honeycomb)
- API 11 (Quantum shift - native Fragments & Action Bar from API 11 onwards)
- API 10 (Last of the "old" Android platforms - there are still people using this)
You should also install
- SDK Tools 24.0.2
- SDK Platform-tools 21
- SDK Build-tools 21.1.2
- Google Play Services SDK
- Google USB Driver
Optional:
- Offline documentation for each SDK Platform.
- Platform source code - useful for a look under the covers.