I'm planning early retirement in the next 12 months. My friends who have retired have given me the following advice: for a year before they retired, they wrote down every single thing they bought - from gas to a stick of gum.
Once a month, they reviewed the list and realized what they were wasting their money on. By the time they retired, the list had become their post-retirement budget.
They did not deprive themselves of anything - they just set their priorities. Their number 1 priority was retirement.