If you don't use any Bluetooth peripherals then saving battery is probably the priority. Heres how to disable Bluetooth on startup.
Just edit /etc/rc.local and add this before the last line (exit 0):
# /etc/rc.local
rfkill block bluetooth
# if you have a thinkpad then you may need this line too
echo disable > /proc/acpi/ibm/bluetooth
exit 0
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