Do we need to install intel x86 Atom system image for all API levels?

Question

I am new to Android development and just installed the new Android sdk with Eclipse and ADT bundle. From this question, I knew about installing Intel X86 system image.But, I have one confusion about installing intel x86 for which I coudn't find any solution on internet.

In SDK manager, Intel x86 system image installation options are shown for each API level as in the picture.

image is here (since I have no privileges. Hope someone will correct it)

So, my question is that Do we need to have intel x86 system image for all API levels?
(I am making an application which will support from Android ICs to kitkat.)

Solution

Short answer: no, you don't need to. When I am actively developing an application, I'll pick a target API level and just use the emulator for that API. It's just like only having one phone to develop on - while you're working, you can only really use one at a time, anyway.

When it comes time to test, however, my advice is to run your app on as many different configurations as you can get your hands on - including different API levels. Now, one thing to keep in mind is that even though the emulator images are all official and provided by Google, they're not a replacement for testing on actual devices. Your app will have different performance characteristics in the emulator, and there are often device-specific bugs (industry term "quirks") that you won't find with the emulator (and some bugs that you'll find only on the emulator).

So, my overall answer is no, not really. Download and use whatever emulator is your target API, maybe download and also develop occasionally on the emulator for your min API, and then try as much as you can to do final testing on real devices, only falling back to emulators whenever you're unable to get a real device with a specific configuration.