While listening to stuff!
I use them while waiting for other things, while watching anime if the background noise level is high, I also use them while my daughter is listening to kids music on the stereo, or to let her listen to kids music on them. Kid's music will slowly drive you insane. Using during study times is good if the music is something you've had for awhile, it helps cut off the background noise.
If I ever started writing again I would listen to music while writing. If you match the tempo to what you are writing the words flow out easier.