Not sure when reviewing code became a habit, but it is now part of routine before deploying new code to production.
Git diff is really helpful and lets me know of the new code being pushed.
It always surprises me that during review I notice conditions or logging methods that I missed adding to the code. There are less surprises and errors in production environment.
I use Beanstalk to deploy code to production and would highly recommend using this, if you are still deploying code via drag n drop using a FTP client.