The cost will be much smaller than the taxes you could have to pay.

It's like with any business, vertical integration has is pros and cons, and you won't fully understand the tradeoffs until you are far down the line.

And they all have the same lines how they are the best agent out there . 

This isn't as hard-lined as many people think.

My guess though, assuming that QBI doesn't get extended, is that it'll either keep getting carried forward and become a useless extra line item on a tax return to potentially be used in future legislation, or that it'll disappear completely.

There is a silver lining.

Is there a specific legal/liability reason why you separate your LLCs by "line of business"?

So if you buy a 5 bedroom house and rent the spare 4 bedrooms = you can still sell tax-free under the 121 (you just pay back depreciation) If you buy a duplex and rent 1/2 and live in 1/2.

It is a duplex near scranton PA. the Mortgage is about $2,400 and each tenant pays $1,550 monthly in rent so I make about $700 in cash flow monthly.

Get a full inspection and a sewer line scope.