You can purchase multiple properties. 

I have had multiple roofers look at it, and they all recommended reroofing with architectural shingles which are supposed to be more wind resistant.

I have come across multiple opportunities this way.

He's on SSDI (Social Security Disability Income) at just under $1,500 a month and he wants to do some wholesales to make some extra income.Lets say he does a deal or multiple deals and makes any assignment fee on it/them and the profit exceeds 1.5k which is higher than his disability per month.

Similarly if somebody wants to rent for multiple months right away at an attractive rate, you might take it too, especially if it's in the low season.

We manage multiple long-term rentals in Indianapolis and use Buildium as our management software, with Tenant Turner integrated for showings.

Go to Etsy and search for "rental property tracker," and you will find hundreds of nice spreadsheets to track 10-20 rentals, usually for under $10.Software has extremely helpful features like online payments, marketing syndication (click a button, and your property is advertised on multiple sites), electronic document review/signing, maintenance tracking, and owner reports.

I know some investors that have multiple LLCs for their properties, but those tend to be fix/flip developers. 

The 500-hour rule means spending at least 500 hours actively managing your rental property, which could include things like tenant communication, maintenance, and bookkeeping.You can also group multiple properties together as one “activity” to make reaching the hours easier.

As a new home builder myself in multiple markets..