Android debugging can be a fairly intense process when using Unity. There are times your app will crash or not work correctly, and finding why can be a real pain.  A couple of things I do to make adb more usable.

Use ‘adb logcat -c’ to clear the logcat buffer.  I’ll do this after killing my app using ‘Advanced Task Killer’.

On the Mac, use CMD-K to clear the Terminal window in which you are running adb.

Use ‘adb logcat -s Unity’ to have logcat only display Unity Debug.Log messages – which you sprinkle throughout your code.  This keeps the logcat display from printing all the normal stuff you see when you run it in it’s default mode.