Quoting Jerry,"You will get advice from southern growers who will tell you that they don't until temps get way lower. Their growing conditions are totally different than growers in the north who must move their plants indoors for a large part of the year."
I can't find the exact post. But the above touches on why northerners protect sooner with milder temps than Florida protects. Acclimating to indoor temps... I have heard him also say protect at 60F. But he said his own he never allows to go below 65F. So I feel that, is my goal. For he apparently feels its important to keep his above 65F. Mine never sulk, or drop leaves transitioning in or outside.
Again quote ,"I find that even though my indoor growing conditions are very good with high intensity lighting and temperatues that stay above 65F."