If you'll owe money on your return, you'll definitely want to file an extension.
Please
see the TurboTax FAQ “What if I can’t pay my taxes?” below, if payment is an issue.
https://ttlc.intuit.com/replies/3301261
But also see "Do I need to file an extension if I'm getting a refund?" below.
https://ttlc.intuit.com/replies/3931358