To Clean or Not to Clean Before a Major Reno

[Vega F.]

A tenant who leased her unit for over ten years recently passed away - the unit is in horrid condition. By horrid I mean that one of the extra bedrooms served as a puppy pen and now has a foot or two of poop on top of carpet and ripped pillows. The poop has since been strewn throughout the house.

Now, I am eager to get started on renovating this property but before I do, I felt it necessary to hire a professional cleaning company with the goal of making the unit a safe working space. 

My mom, who has owned rental properties of her own for 20+ years, says paying a cleaning company is a waste of money given the scope of work on the rehab. 

What are your thoughts? Would you professionally clean the unit before stepping in it?