The time when a newly formed habit is really put into test is when we are under stress. Stress causes us to reboot to last saved brain settings that have been known to work. The habit may look like it has been ingrained completely, but we can truly find out only during conditions of stress.
The next time you are under a stress of any sort, observe yourself. Are you rebooting back to safety or are you able to stick to your guns and continue the good fight?