Is a legal entity needed for your first property?

[Jacob Eddy]

Just got finished reading the chapter on setting up legal entities in the Tax Strategies for the Savvy Real Estate Investor.  Are legal entities or LLCs needed when you acquire your first rental property or is this more for someone with a larger portfolio?

On a side note, when I read the deductions chapter, it said you could even write off the Biggerpockets book since it is for growing your business!  Sure it was only a $15 book but for conversation purposes, can I write off this book even if i don't own a rental property yet?  :)