Three reasons why I asked this question. Only #1 applies in 2021. The other 2 bullets are from previous years.
1) I am a 50% owner of an LLC that owns rental property in Florida. We have owned the property for about 10 years and we have management company that takes care of everything. I go months, sometimes years without stepping foot on the property. The LLC has NEVER been required to file a Florida return.
2) I have a very small business that does home improvement projects. Once or twice over the last 8 years, I have done work 10 miles away in another state. I only filed taxes in my home state.
3) As a consultant for a major IT vendor, I worked all over the country. I only filed taxes in my home state.
