How should I file long form?

[TomK]

There is no more "long" form, just Form 1040 with schedules added as needed.  However, if you're referring to "itemizing" instead of taking the standard deduction, then you should itemize as long as it makes financial sense to you (i.e., helps you financially).

As a result of these and other tax law changes, our estimate is that nearly 90% of tax filers will now be taking the higher standard deduction, up from around 70% last year. And if you're in the 90% group, you won't see a change in your refund after entering your mortgage interest and property taxes.

The 2018 standard deduction is nearly double the 2017 amount:

$12,000 for Single

Add $1,600 if 65 or older

Add $1,600 if blind

$18,000 for Head of Household

Add $1,600 if 65 or older

Add $1,600 if blind

$24,000 for Married Filing Jointly or Surviving Spouses

Add $1,300 for each spouse 65 or older

Add $1,300 for each blind spouse

$12,000 for Married Filing Separately

Add $1,300 if 65 or older

Add $1,300 if blind