The standard deduction for a single filer is "only" $6,100. It doesn't take a very large mortgage to combine with real estate taxes and other potential deductions (State Income tax/Sales Tax) to move you out of the standard deduction category.

When I've had a mortgage, I've never taken the standard deduction. When I've not had a mortgage, I've never itemized.

Not really, because you can take a sales tax deduction if you itemize. Sales tax deduction + mortgage interest deduction probably gets you over the hump. If you're in a state with property taxes you can deduct those as well when you itemize.