Because if you do, they will provide you monthly accounting statements as well.

Currently I live off my investments and can easily retire.

He has provided very creative solutions for my clients currently and in the past.  

You can register your STR's at the link @Carrie Foley provided and the current response time is ~2 weeks based on my submissions.

Implying that an individual can become expert and easily operate in multiple states4.

Thank you for providing such needed info!

CA taxes residents on worldwide income but may provide a credit for taxes paid to other states.

Hey @Vicente Hernandez - Can you provide some examples of what you would consider a "referral type"? 

And on top of that, in a region like ours where construction labor is an acute challenge, they provide a great solution.

Here are some of the highlights: quickly set up bank accounts for each property and sub-accounts under those for things like security deposits and CapEx; virtual credit cards tied to each property; quick transfer of funds; ability to send money back and forth to tenants (some platforms are for collection only but won't let you send your refundable deposits back to your tenants); easily categorize every transaction into IRS Schedule E categories for reporting taxes; ability to split transactions; tenant management from vetting to drafting lease agreements to collecting rent.