Running Spotify on Mac or Windows? You should be aware of this bug:
On my computer it has written about 200GB in a matter of a couple of days.
Its a serious enough issue, especially on SSDs where you only have a limited amount of read/writes.
The problem is fixed in version 1.0.42, so make sure you are not letting Spotify idle on your computer if you are not on 1.0.42 (or higher).