Benefits of the New API - Learn OpenGL ES: For Mobile Game and Graphics Development - page 12

Figure 1-8 . Cleaning our project
Note Although it is not necessary to remove all the warnings from
your application (because the application can still work with these
warnings), get into the habit of clearing them, especially in cases in
which unused imports or other redundant code can cause your ap-
plication to be larger than necessary.
The few lines that cause warnings may look insignificant now;
however, later in the topic, we will be dealing with examples in
which those lines might add up to bloat the performance of your
application. The Android lint tool always highlights such warnings
and, in some cases, can optimize the binaries by itself. This does not
happen always, however, so remember to clear those warnings.