Buy a bag that is rated at least 10 degrees lower than what you expect outside temps to be
Read the fine print. A few years ago I looked at a bag rated to 20. In the fine print it said that their ratings were for the temperature that you would keep you alive, not comfortable.
“In a time of deceit telling the truth is a revolutionary act.” ― George Orwell
It's not over when you lose. It's over when you quit.
