Only boil a kettle to the amount to you need, don’t fill it up.
switch off phone/computer chargers and other plugged in (non essential) electrical items when not in use. These run even when not charging.
my friend who is a dentist once told me the best tip he could offer to protect your teeth is - when brushing your teeth don’t rinse the fluoride (saving you potential dental visits)
what are your personal day to day moneysaving and habits that someone else might not know?