If you wear different hats, it means you have several different jobs or roles.
"Alice is presenting the news at the weekend."
"Really? I thought she only worked behind the scenes?"
"She presents every weekend - she wears many different hats."
I'm not going to work – I'm wearing a different hat today. I'm going to be volunteering at my local youth club.
My brother wears many different hats: he works as a swimming teacher during the day, at night he works in our local pub, and at the weekend he helps out at a rowing club.
Don't confuse it with
If you do something at the drop of a hat, you do it immediately, on the slightest signal.
Johnny Depp is gorgeous. I'd marry him at the drop of a hat!
This year marks the 101st anniversary of the founding of the Republic of China, which was celebrated in Taiwan this week during the island's National Day. Dancers wearing elaborate costumes performed in front of the Presidential Office in Taipei, and members of the military guard marched as part of the celebrations.