Possible Clues:

• Reason to keep something under your hat?
• Time to feature any of the three theme answers?
• When one might wear a hat
• Time to change the locks?
• Difficult time with some nasty shocks?
• Dreadful time to have to cope with parting?
• Model's dread
• Period when all goes wrong
• When everything seems to go wrong at the same time?
• Reviewed, I had a drab year, awful time