Retirement tax questions

Thank you for the reply.  A clarification, though:  Yes, SS is my only income, but Box 5 is actually over $20,000; however the "taxable" portion (as calculated by Turbotax) is indeed below the $13,850 exemption level.  So I normally wouldn't have to file the return.   But since I'm filing as "Married Filing Separately", I wasn't sure if not filing (while my wife does) would raise any red flag.