It seems a lot of folk running android 4.4.2+ have had trouble getting spotify to use an external SD card for its cache. I just bought a card for my android so I thought I'd give it a try and it worked!

My mobile

• Samsung Galagy Note 3 - android 4.4.2
• Samsung 64GB SDXC UHS-1 card
• Spotify 1.1.0.113

Steps I took

• Cleared spotify cache from options
• Uninstalled spotify
• Inserted SD card
• Used file explorer to delete residual folder \android\data\com.spotify.music in internal storage (also delete the folder com.spotify.mobile.android.ui if it exists)
• Installed spotify music
• Played some tracks

I still see a com.spotify.music folder in internal storage but it's empty now.

If you have previously been using spotify with an external SD card, I recommend that, in addition to the steps above, you reformat the card in the phone before reinstalling spotify music.