Investors & landlords

The "if required" part is maybe where I'm tripped up. And this may be a subjective question, but based on anyone's experience and expertise...

  • Is it worth the hassle to me and to that state to go back and file returns for the last several years?
    • Is that still called "amending" the return if I never filed one in the first place?
    • What factors could help determine if it's worth doing this?
  • And I would then also need/want to amend the returns for my home state as well for each of those years?