I've worked with a lot of property managers and landlords on mold remediation projects and my experience has shown me the best time to find mold is when the property is completely vacant, and here's why.First, when you find mold you should verify that what is found is in fact mold.

How was your experience and did you have any regrets at all? 

While I am not a full time flipper *YET*, I have strong knowledge and experience in the architecture, design, and construction industry.

Even if you get a professional radon test which reads the levels over a period of about 48 hours, they are relatively inexpensive ($150-$250 in my experience).

My experience suggests that if cost is a deciding factor, you probably don't need an LLC.

As they've gotten settled the experience has become a nightmare. 

I appreciate the detailed suggestions and personal experiences you shared.

Quote from @Eric Hajdu: I am certainly not a tax expert, but fwiw, I just looked at my closing statement from the purchase of a Brooklyn multi-fam and as purchaser, I paid the following taxes:Transfer Tax Additional Transfer(mansion)taxTransfer Tax Supplemental NYC(mansion)taxMortgage Tax 1st mortgage Thank you Eric, the real life experience is the best reference!

Andrew,Man so much good knowledge has been dropped on this topic already so there isn't much to add other than its all on your personal experience level as well as your willingness to take risk.

I rather not speak poorly about a company in the public forum, I'll DM you and maybe you can let me know if you've heard of them or had any bad experiences.